Overclocking i7 860

i have a radeon HD 5870, 6gb ddr3 1333mhz, and a liquid cooled i7 860.
id like to know what i have to do to overclock my cpu to at least 3.5 ghz up to 4.0 ghz(from what ive heard 3.5 is safe with a stock cooler and 4.0 should be fine with lquid cooling and wont use too much voltage). i would like it if i could overclock it so that my cpu wont bottleneck my gpu, however much that is.

i bought my computer from alienware, so some of the properties in the BIOs are locked and i have a bad stock motherboard.
if i need to change the voltage to get the oc i want, how do i check the voltage limit for my mother board?
can i get a new BIOs for the alienware's intel stock motherboard?
if so, where?
or do i have to buy a new motherboard?

thanks for yur help in advance!

What do you mean by "I have a bad stock motherboard"?
Which options in the BIOS are locked?

ive heard alot of people saying that alienware uses intel's stock motherboard, like $50 motherboards. they might be wrong, but it was hard to find any information about what motherboard alienware uses so i wouldn't doubt it(the only information i got was that they use x58 architecture thats compatible with i7s).

i don't exactly remember, but there were alot of voltages i couldnt change. i can change the base clock, multiplier, and the memory timings.
im gonna go check after this post.

EDIT: this is what i can configure
general:
memory ratio
multiplier
DMI ratio
dRAM configuration:
tCL
tRCP
tRP
tRAS
tRFC
tWR
tWTR
tRRD
tRTP
1T/2T timing
overclock configuration:
BLCK
PCI-E frequency
spread spectrum
overvoltage configuration:
DDR3 memory voltage
Dynamic CPU Vcore offset
DMI and Uncore Voltage