OSX Lion and TS3 - Patch released, fixes graphics issue, causes problems with Town Life, GURUS?

ok...so...this is probably going to sound stupid on my part....but here it goes.

I have an IMAC, so ....just the one screen/all in one......no tower. Is there any way to upgrade my graphics card and if so, would it work? I currently have a NVIDIA 9400. I have plenty of space, as my computer is solely used for the sims and FB..lol I have enough speed and I meet the requirements/minimum by a long shot.... but this stupid graphics card blows. So. again.....is there any hope for me beside waiting for someone to come up with a fix???