Question on Mirroring and changing default database (Disk space issue)

I wanted to get some advice here before I do something drastic!

So, I have my primary SQL Server on a physical machine and a mirror on a VM (Content, Admin and Admin Content are mirrored) . I had SQL Maintenance plans that took transaction log files backup and truncated it every week to keep free disk space manageable. The Primary Content Database was running off the mirrored server before the problem happened.

Few weeks ago, my scripts stopped for some reason. My disk became full. I was able to get some free space on primary. But the mirroring is paused and can't resume as the free space on the physical is too low for the mirroring to resume. 

I'd like to remove mirroring and make my MIrror (VM) as the primary. I'd like to run this setup until I'm done with my upgrade to 2013 next month. What steps should I take to remove mirroring and make the mirror server as the primary? 

Thanks.