Unless you want her to lose drop the silver helms, they suck... Field Dragon Princes, and to be heavy cavalry at say 2000pts, you field 2 units of 5 dragon princes with a noble in each for good hitting power. Field some ellyrian reavers for re-directs and etc, and maybe some tiranoc chariots for those wonderfully long chariot charges.
Some mages for magic defense and fill your core with some archers. Maybe have one unit of White Lions or Swordmasters to help give you a stronger center to your army, if you really want an anvil and hammer tactic field phoenix guard...
Or you can go heavy magic, and field 2 units of 6 dragon princes, and use character slots for mages...
Cavalry is really just, small units of 5 fast-cav or hammer units of 6 heavy cav....
Very few full cavalry units out there, though I do know of some, like bretonnia and tomb kings...
Then again I'm not a high elf player (anymore, i was for a little bit)...
