Well for a start you'll need to have twenty warriors to fill the compulsory two troop choices. I would take away the wraith- for the extra warrior.
Also it would probably be better to play 750pts as your more likely to play a game with someone with 750pts than 700pts. The points battle usually go from 440pts, 500pts, 750pts, 1000pts, 1500pts, 1750pts........
For eldar, since most of the eldar aspect warriors and the guardians only have a 4+ save or worse, I would use
Necron Lord 100pts
10x Warriors 180pts
10x Warriors 180pts
5x Immortals 140pts
5x Immortals 140pts
Some nice AP 4 goodness plus the immortals will be wounding most eldar on a 2+
If you don't have the models- you can proxy. Experiment with lists till you find one you like