So I play Eldar in this game since that's the only faction with girls, and I decided to get into tabletop, bought some stuff from FLGS and have around 1200 points of Eldar now but I'm unsure how to expand to 1500 pts.

Here is what I have currently.

2 Farseer Skyrunners w/ Singing Spears

3x4 Windriders w/ Scatter Lasers on each

2 Fireprisms w/ Shuriken Cannon

1 Wraithknight w/ Ghostglaive, scattershield, 2x Scatter Lasers

Now to get my force up to 1500pts for local store stuff, I can either add 3 more Windriders with Scatter Lasers and 3 Singing Spear Warlocks and run my Windrider squads as 3 x 5 Windriders with Warlock Skyrunner leaders, or I can add 2 Crimson Hunters for anti air and some extra fire support.

I basically got what I have now by buying two of those Start Collecting Eldar box sets, adding 2 boxes of Wind Riders and a Wraithknight(which was what decided the colour scheme of the army by being done up like Eva 08 from Evangelion 3.0).

I was leaning towards Crimson Hunters so I have anti infantry, anti tank, WK for killing enemy choppy stabby things and anti air, but I was told at the FLGS that with the 2 Farseers using Runes of Fate and Divination Primaris powers I could basically just gun down enemy flyers through brute force with massed Scatter Laser fire thanks to rerolls, the Warlocks being around to provide some extra buffs and warp charge.

I wish I could help on specifics but I am a Imperium/Mechanicus Player. but I say go with what your leaning towards and always have an eye out for having a backup plan for any general strategy you go with.

He has a scatterbike/wraithknight army, he doesn't need any "backup plan". Hell, I'd say this army doesn't even need a plan in the first place...