First Time Build + Dell Studio XPS 9000 + $1500 Budget = Gaming PC?

Hi Guys!

I much appreciate you taking the time to read my post and rest assured I am grateful for ANY feedback and tips. I will try and provide the most data I can to give

My Tech Experience Level: 2 (out of 10)
I have built homes with my bare hands but never a PC, so I am not a complete disaster when it comes to following plans and executing them properly. My PC knowledge and experience in construction is such that I can open my case and identify what is the power supply, hard drives, wireless, card, etc, but I am certainly not versed enough to identify the responsibilities and proper connection for every cable and each little 'dot' or 'bump' on a motherboard or video card is/does. (Hope I am making sense here...)

My Goal and Needs:
I have a Dell Studio XPS 9000. I am currently entering grad school so I am looking for something that will meet my daily needs as far as a student plus looking for a good gaming rig that candle handle my most played online game of SWTOR.

Currently this Studio XPS 9000 only reaches fps of high teens and even drops to single digits, and that is on the lowest settings SWTOR offers w/ shadows off. I am fairly certain my video card is lacking. However, I am looking for some input as to whether or not this machine should/could be simply upgraded, if I can 'salvage' anything still worthwhile from the XPS 9000 and use that in a new build, or if I should just start from scratch with my $1500 budget and build a new PC?

Completion Date Goal: 2/14/2012 (Funds on hand and ready to go!)

What I am working with -
Budget: $1,500 USD
Current System: Dell Studio XPS 9000 (6HJYJM1)
Studio XPS 9000, Intel Core i7-960 processor (8MB L3 cache, 3.2GHz)
12GB DDR3 SDRAM at 1066MHz
AMD Radeon 5450 (1 GB)
1 TB Serial ATA 2 Hard Drive 7200 RPM
Windows 7 Home Premium, 64bit, English
Adobe Reader 9.0 Multi-Language
Roxio 10.3, Easy CD & DVD
Cyberlink Power DVD 8.3 Blu-Ray Disk Playback
Dual Drives: DVD+/-RW with BD Combo
Soundblaster X-Fi Xtreme Audio

What I DO NOT need: Monitor, printer, keyboard, mouse, speakers, cable/dsl modem, wireless router. Basically, peripherals are taken care of.
Dell Studio XPS 9

I thank you in advance for any assistance or advice you can give me!