Dell Vostro 1000 Processor Compatibility

Hello,

I am trying to upgrade my girlfriends computer a bit and would like to swap out her CPU and RAM. She currently has the MD Athlon X2 TK-57 1.9GHz Dual Core. Its a socket S1 processor and it scores 924 on a benchmark. I have also found the following CPU's that have the same S1 Socket and am wonder which/if any will work for this computer? The MOBO is a OPM854

Processor                                 Benchmark

AMD Athlon II P340                  1302
AMD Athlon II P360                  1347
AMD Turion II P520                  1405
AMD Turion Ultra M600           1484
AMD Phenom P650                 1630
AMD Phenom II N660              1833

As you can see the Phenom II N660 will nearly double it IF-F it is compatible.

Does anybody have any insight on this?