Houllier was discharged from hospital on Thursday - just eight days after being admitted suffering from chest pains.
The Frenchman, who had major heart surgery while in charge of Liverpool, is almost certain not to return to Villa in an active role this season.
Recovering: Gerard Houllier has been released from hospital but may not return to the dugout this season
A significant question mark still remains over whether Houllier will be back at all given his medical history even though McAllister is positive that will eventually happen.
But the caretaker boss is adamant the wheels will still be in motion at Villa regarding dealing with attracting new signings, players leaving and those who are currently out of contract.
McAllister said: 'All these things that from the outside we seem to have to deal with over the next few weeks, we've been looking through already.
'Of course, it would be better if Gerard was here, but everything is place for things to move on.
'Whether it be attracting new players, or players coming to the end of their contract, a lot of decisions have already been made.'
McAllister added: 'I agree with people who say the upheaval is unneeded but as a group we've become very close with the chairman (Randy Lerner) and chief executive (Paul Faulkner).
'There is a plan to move forward which is already there.
In our thoughts: Gary McAllister (front left) leaves Houllier's seat empty
'As much as it would be ideal if Gerard was here, it can be done from his home because we're down the line on a few things.
'I don't have to give anything away, but I'm talking about people that might want to come here, people we want to try and attract here, people that want to stay, people that might have to find a club.
'We know the positions where we are strong but we also know where we need to strengthen. It's ongoing and you've got to be like that, you've got to be prepared to go into the market and get these deals through.'
McAllister has been delighted at the progress Houllier has made during the past week which has given him cause for optimism about his future.
But he accepts Houllier will ultimately make that decision.
Getting behind their man: Aston Villa fans show their support for Houllier
McAllister said: 'Can Houllier return to management? That's the big question down the line.
'That will be after he speaks to friends, family and people he respects but, most importantly, the doctors.
'There's no rush to be made on that decision.
'I'm sure he'll be recovering over here where there will be people on hand to deal with any queries.
'If he's given the green light to go and gets some warmer weather if it helps, I don't know. He'll be guided by the experts.'
Meanwhile,McAllister downplayed comments by leading sports cardiologist, Dr Duncan Dymond, who has been consulted by Chelsea in the past, that Houllier would be best advised to retire.
Hesaid: 'We are very appreciative of the concern of the guy but he doesn't know the case, he doesn't know the ins and outs of the case.
'Heis speaking from afar and Gerard is going to be advised by the people who are looking after him, the people who know his history.
'We do appreciate this fellow's concern but he does not know the finer details of what has been the problem.'
Meanwhile, McAllister admits Villa midfielder Stephen Ireland has to gain full fitness before his 'real talent' can blossom.
Ireland is returning to Villa to undergo rehabilitation work after his loan spell at Newcastle was cut short by injury setbacks.
It was a similar scenario during the first half of the campaign after Ireland moved to Villa from Manchester City as part of the deal which saw James Milner head in the opposite direction.
McAllister added: 'Stephen is an Aston Villa player. He's our responsibility.
Troubled times: Stephen Ireland has struggled for form and fitness since his move from Manchester City
'When he reports back, he needs to be assessed by the medical people here and then be set a programme to get fit.
'He has had all these problems for a long time now.'
When asked if Ireland will still be at Villa next season, McAllister said: 'He went on loan, it's not worked.
'He's had problems up at Newcastle as well, a number of injuries as well, groin, hamstring, ankle, he's not had much luck.
'There is no doubt he is a talented player but he's got to get fit before we see the real Stephen Ireland.'
?Houllier discharged from hospital but boss is warned against Villa returnWalk away, Gerard: Medic warns Houllier to quit after latest heart scareDoctors query Houllier's Villa return: heart condition 'difficult to treat' All the latest Aston Villa news, features and opinion
?Explore more:People: Gerard Houllier, Gary McAllister Places: Liverpool
Source: Daily Mail
Source: Daily Mail