Help me with my game- graphics problem

Hi all,
I'm trying to play NFS Hot Persuit 2010 on my PC but encounters a problem in terms of slow image processing. Everything is fine while I run the game and intros but things changes when I start my "Career". From this point the game is extremely slow and even the background sound. I'm specifying my PC configuration so that u people can help me out about what is wrong:

AMD x2 - 2.9 Ghz
ASUS M2N68-AM PLUS with NVIDIA GeForce 7025/nForce 630a Chipset.
Integrated Programmable Shader model3.0 DirectX 9 graphics processor
Current shared memory (in my PC): 512 MB
Supports RGB with max. resolution 1920 x1440 (@75Hz)
250 GB Seagate Barracuda
2 GB DDR 2 RAM
19 inc LG Flatron

I dont have a dedicated graphics card but the infos about the minimum requirements I got in order to play the NFS Hot Persuit is totally satisfied by my PC 's specification. Plz help me out guys with ur suggestions.

[One thing more what is meant by "Programmable Shader model" ? Can I change anything out of it ?]

Thanks in advance