Will this work

I was interested in an Alienware PC and I wanted to buy one with these components
I can upgrade Ati 5850 to NVIDIA® GeForce® GTX 260M


Intel® Core™ i7 740QM Quad Core Processor, 1.73GHz
1GB GDDR5 ATI Radeon™ Mobility HD 5850
15.6-inch WideHD+ 1600x900 (900p) WLED
4GB Dual Channel Memory (2x 2GB DDR3)
500GB SATAII 7,200RPM
Slot-Load Dual Layer DVD Burner (DVD+-RW, CD-RW)
Wireless 1520 802.11n Half Mini-Card

If I missed any information please tell me

what's the mobo specs?

I need help the special deal ends tomorrow and not sure about motherboard. It doesn't say anywhere online