First I would check with my supervisor to see what (if anything) is happening with the shift to full-time since there was the acquisition. If he doesn't know what the status is, I would send an e-mail to your boss and CC your supervisor to explain the current situation. You should cover the following:
- Your contract will expire
- There were discussions before the acquisition of taking you on full-time
- If the company is not interested, are they planning to renew your contract
Your new boss may not realize that your contract will expire, and may be expecting that your local office is taking care of it. Acquisitions can be busy times, and the impact to you if it expires is much larger than the impact to your boss (who it sounds like you've never even met).
Changing to Full-time
Because of the acquisition, your boss may not know your contract status, let alone that you are interested and had discussions about coming on full time. By letting the boss know what your interests are, you give an additional option for how to deal with the contract expiration.
Regardless of whether they offer you a full time position or not, your contract will expire in just over 3 weeks. You need to make plans for what to do next, be it joining full time, continuing to work as a temp, or finding another job. It would be a good idea to also ask what the plans are for renewal if they cannot find you a full-time position for whatever reason.
I would write something like this:
Hey boss, I know things have been hectic with the acquisition. I wanted to let you know that my contract is currently set to expire on October 31st (in 29 days!). Before the acquisition I had been speaking with my supervisor and HR here about joining on full-time, but due to the acquisition, I don't know how I should go about discussing that as a possible choice from November.
Regardless of whether or not we can work out full time, I would like to know what the company plans are in regards to renewing my contract so that I can start the handover to my successor if it won't be renewed.
Just be sure to check with your supervisor beforehand, because if you send the e-mail while he/she's already working on it, your boss may be upset with him/her for not handling this sooner.
Here are some other discussions about contract renewal/renegotiation: