Doesnt WORK!

I was really excited about playing this game but unforuntely the lag is so bad that I cant even play. My specs are below, I have upgraded the ram to 8gb and it still doesnt work. All game settings on low. Anybody have any ideas or advice?

Model Family:MacBook Pro
Processor:2.26GHz Core 2 Duo (P7550 or P8400)
Manufacturer:Intel
# of CPUs:1
Codename:Penryn
Display:
Size:13.3"
Finish:Glossy
Resolution:1280x800
Memory:8GB
OS:Lion
Battery:58-watt-hour removable lithium-polymer
Graphics:NVIDIA GeForce 9400M (256MB)
Base Storage:160GB 5400RPM SATA 2.5"
Optical Drive:8x DL Superdrive

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