This is a high-risk, high-stakes negotiation. Not everyone has the appetite for it, and no matter how well you handle it there's a good chance it will blow up in your face. The only good news about the bad news is that unless your manager's manager has an ego so big that he/she is willing to commit career suicide so as to save face, your job is probably safe until the conversion is over.
And as things stand, you'll lose it then anyway.
Here's one other alternative. Be aware that it's just as risky and, from some perspectives, more unsavory:
Approach a local systems integrator (not the one that's handling the conversion) as a team. Let the integrator know that the three of you are willing to join their staff as a team and only as a team, and that once you do the integrator will be pretty much guaranteed your employer's business during the course of the conversion. The terms of your joining: Signed employment contracts guaranteeing jobs for the three of you for a full year following completion of the conversion contract, and training in a new technology with significant market demand.
I mentioned at the beginning that these alternatives are open to you if you're willing to play hardball. If you aren't, here's what you do: Cut your lifestyle back to a minimum and save everything you can. Put it in certificates of deposit or someplace else safe.
You'll need it to cover your period of unemployment once the conversion is finished.
Good luck. You're in a situation that has no good alternatives, so the best you can do is to choose the least of the available evils.