The links for the GP 10.0 downloads on Customer / Partner Source are provided in the last reply I sent..
Here is the direct link for all the SP's of Rel. 10.0:
I suggest that you install the latest available (Year-End update 2012 includes SP5) for GP 10.0, so you won't have to bother. The SP's are always all-inclusive for GP, which means you should be able to apply SP5 straight onto the base installation of 10.0.1193 or SP3 HF (10.0.1301).
If you don't care about the latest US Payroll update, you can just stick with SP5 released on 2010/8/18 :