Yeah I agree, as I'm sure many others will also, that your system is a bit old for SWTOR.
I have a core2duo o/s @ 3.2Ghz, a GTX460 (o/c), with 4GB RAM @ 1066 and I'm looking to upgrade because with custom settings my fps drops to around 25 sometimes (some options high some low, some off) - all running at x1080.
I would head over to tom's hardware, they've done some benchmarking on swtor.
As a guide, I'm lookling at the i5 2500k, with something like a GTX560Ti (2GB). That should play it nice and smooth on high gfx.