Hi,
Your first stop is your cpu's home page, (link below), here you will find the rec voltage and temp's, unless your going for a really high o/c i have found it best to try and keep to their recommended settings, although you may have to tweak the voltage a bit but that is unlikely, visit other o/c sites and see what other people are doing with the same type of cpu, i was able to learn a lot by doing that, as for the temps you can see mine at idle but mine is o/c to 3.7Ghz so they will be a bit hotter, they max out around the 50c mark playing Far Cry 2, and Crysis, speedfan and cpu'z are two good tools that are worth downloading, as for your the temp's i would see what other people are getting from theirs, they dont seem too hot to me but i have just come off a striker 2 motherboard that idled at about 50+c and maxed out at about 65c, Asus said that was good, lol, let me know how you get on.
CPU, Processor Information | AMD 
just keep clicking on picture untill you can see it.