Id say that you are in the norm with those temps.
My Phenom X4 9750 with stock heatsink and stock clock rate (2.4Ghz) was idling at 51C, and was in a room with an ambient temp of 20C.
After adding an A70 Corsair cooler and overclocking it to 2.9Ghz, I idle at exactly 40C. Honestly, id say your stock heatsink is doing a fine job.
PS: Learn from my experience, and research your aftermarket cooler in regards to its mounts to your AMD/Intel processor socket types. The A70 I mounted will only mount vertically (air flowing north and south) when with an AMD socket, and runs horizontally with Intels sockets. You CAN modify it if you look up the methods, but just be aware if you do choose to go aftermarket aircooling in the future.
Good luck man!