sony vaio ns10l/s upgrade

i have a sony vaio vgn ns10l/s with a t3200 cpu 2ghz/1mb l2cache/667 fsb and it has a gl40 express chipset i want to upgrade to the fastest possible cpu my laptop can handle i know its a socket p connnection or thats what i have loooked up. i wanted to get a t7200 but i think that its a different socket connection. but then i was looking at the t5850 which is the same connection it has more cache and more mhz but would it make alot of difference in performance will it be worth 90$ i know its a socket p connection could some one please help and tell me what would be the best way to make my laptop faster. thanks