If this is the machine listed in your specs, I'm amazed it runs at all.
- Processor Intel Core 2 Duo T6500 / 2.1 GHz
- Multi-Core Technology Dual-Core
- 64-bit Computing Yes
- Data Bus Speed 800.0 MHz
- Chipset Type Mobile Intel GM45 Express
- Graphics Processor / Vendor Intel GMA 4500MHD Dynamic Video Memory Technology 5.0
- Video Memory 128.0 MB
- Max Allocated RAM Size 1759.0 MB
Your video device is using shared system ram on a laptop, which traditionally are horrible gaming platforms to begin with. That you are gaming on that system with any kind of tolerable rate to begin with is amazing to me.