New to OC'ing, need advice with a 9850 BE

I want to overclock my 9850 BE. I know how to do it through the BIOS, but I don't know how much this CPU can take, and I'm nervous to try to OC this computer. I don't want to mess with any settings that could ruin a warranty without knowing that the computer won't break, because I'm only 15 and it took me an entire summer just to save up the money to buy my computer (I wouldn't be able to pay for replacement parts). So, I was wondering if anyone knew how high I could safely raise the FSB and multiplier up to. I have a Hyper 212 cooling fan on it, along with four large case fans. All together, the fans allow the CPU to run at about 28C idle, and about 38C under full load. I don't know what other info you need to give me some good estimates as to what it can take, so here is the computer's specs:

Motherboard: MSI K9A2 Platinum (rev. 1)
CPU: AMD 9850 BE with a CoolerMaster Hyper 212
RAM: 4gb (two sticks) Patriot Viper 1066
HDD: Seagate 7200.11 500gb
GPU: ATI MSI 4870 factory OC (512mb)
PSU: Corsair tx750 watt
Case: Antec 300 with two additional fans added to the front


Any tips would be greatly appreciated!