I can say this safely for two reasons.
1. Most laptop video cards are not user-upgradeable. Even if you can get the parts (in excess of $300 usually), installing is fraught with disaster.
2. Laptops in that milieu use the ATI Radeon 9000 and 9200, which can be gotten sometimes in 64mb, but does not support DX9.
I have a Sony Vaio V505 with a 32MB ATI Mobility Radeon 9200 graphics chip, which only supports DirectX 8.1 (I think?). I would like to replace it with something that supports DirectX 9.0 and has at least 64 MB of memory.
Any suggestions on what to buy/where to buy it?