Hi there
Sounds strange, checked your PC and it seems to fit the requirements. Weird that it's lagging even when all settings are on low. Have you tried altering the settings in your video card control panel? It's a bit annoying but if you try out all the settings in there and keep logging in and out (you have to restart game everytime you change settings in gfx card control panel to see the changes), you might find something that works. Also, I found that downloading a program called "D3D Overrider" makes the game a lot smoother. It overrides vertical sync from game and gfx control panel, gets rid of tears, generally seems to make the game a bit smoother for me.
You can also download Prio Priority Saver - http://www.prnwatch.com/prio.html and install it. After this, open SWTOR and login and run the game. Alt + Tab out so you go back to windows. Then press ctrl+alt+delete to open task manager. Then click the button at the bottom with the administrator icon which says "See processes from all users". Left click swtor.exe and set the Priority to "High" and make sure that "save priority" is selected. Do the same on launcher.exe. This gives you a few extra FPS in my experience
Game Booster and Advanced System Care actually seems to slow swtor down, so don't even bother with them. Make sure you close as many processes and programs that you don't need running while you're running the game...
Besides the programs I suggested, just keep messing around with your graphics control panel settings until you find a combination that works..
I know it shouldn't have to be this difficult to make the game work but it's worth trying to get it a bit smoother
Oh and also, if none of the above work, try googling "SWTOR tweaks config.cfg" and check out some of the results. There's a lot of guides out there which will help you edit the client configuration file to make the game run smoother.
Hope this helps and good luck