Technically speaking, your video card isn't supported, so I'm afraid getting much better performance out of it will be difficult at best. So there are a couple of things you can do to try and improve performance:
1) update graphics drivers: I'm not sure what operating system you are using, but you should be able to get
the latest drivers here.
2) update directx: This was probably done when installing WG,
but just in case
3) turn your graphics setting down: you mentioned resolution is on lowest, but make sure your graphics settings are down to 3 as well
4) Turn off as many background programs as possible: Here are some handy steps for turning everything off :
To Boot Clean in Windows XP
1. Click Start --> Run --> Type MSCONFIG --> Click OK
2. On the General tab, choose Selective Startup
3. Uncheck Process SYSTEM.INI file
4. Uncheck Process WIN.INI file
5. Uncheck Load Startup Items
6. Click on the Services tab
7. At the bottom, check Hide All Microsoft Services
8. Uncheck all boxes in the window or click the button labeled Disable All
6. Click OK
7. Click Restart
8. After reboot, run game to see if it works.
After performing the necessary steps, restore your system by doing the following:
1. Click Start --> Run --> Type MSCONFIG--> Click OK
2. On the General tab, choose Normal Startup
3. Click OK
4. Click YES, when asked to restart your computer