HP upgrades

i'm mostly new to all this, but here we go...

i got a Hp model a6000n
specs are as follows:

vista home premium

Base processor

Athlon 64 X2 (W) 4200+ 2.2 GHz

*
2000 MT/s (mega transfers/second)
*
Socket AM2

Motherboard

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Manufacturer: Asus
*
Motherboard Name: M2N68-LA
*
HP/Compaq motherboard name: Narra-GL8E

Memory

Component Attributes
Memory Installed 1 GB
Maximum allowed 8 GB (4 x 2 GB) (64-bit OS)

4 GB* (4 x 1 GB) (32-bit OS)


Speed supported PC2-4200 MB/sec
Type 240 pin, DDR2 SDRAM




now what i want to do is get an SLI ready motherboard

i got a great deal on two geforce 8500gt graphic cards and want to utilize both.
i realize i will also need to up my power. i got that, no biggy.
what i want to know is what type of motherboard can i use to still keep everything else the same (just want sli) and still use the same memory and all.

if anyone can help me out that'd be awsome.
thanks