okay, i would choose the 2nd option with AMD Phenom™ II X4 Quad-Core Processor.
If u want to use 4890 then i suggest to upgrade the PSU as well..
4890 need pretty much power, i doubt the PSu which came with HP is enough..
Hmm another question, ive always been an intel-man , are AMD's good processors for gaming, especially games that are cpu based like wow? and second off it doesnt list what psu the HP uses so how will i know if my gpu can handle it?