Your HSF is not the best but you will be able to OC your CPU higher with it.
First you got to find out if the multiplier is unlocked... you can do this by trying to increase your multiplier to 14x and see if you get a CPU speed of 1860 MHz after that. If it refuses to boot try upping the VCore a little (0.025-5V), but keep a watch on your temps. If it just uses the normal multiplier 13.5x then it is probably locked.
If multiplier increasements don't work try increasing the FSB. Do this a couple of MHz a time and check if your system runs stable. If not and the temps aren't very high increase the VCore a little. Keep in mind that increasing the FSB also means increasing the memory... so it could be that your memory prevents you from a higher overclock at a certain speed. A good program to test memory stability is Memtest86 and a good program to test CPU stability is Prime95. If all runs stable continue increasing the FSB... if not back off a couple of MHz and see if that makes the system stable again.
My dual-PSU PC is so powerfull that the neighbourhood dims when I turn it on