AMD Phenom™ II Quad-Core Processor P920 1.6GHZ/2M
AMD Phenom™ II Triple-Core Processor N830, 2.1 GHz
AMD Turion™ 64 X2 Dual-Core Mobile Technology Processor P520, 2.3 GHz
AMD Athlon™ II Dual-Core processor P320, 2.1 GHz
AMD V Series processor V120, 2.2 GHz
are the processors that the K52N is supposed to support (factory options, I think). If any of them is better than what you have, that might be an option. But upgrading the processor on a laptop? I personally wouldn't go there... You're probably much braver than me.