3 feats
Hi!
Don't have my book with me, but i would say take Spellcaster prodigy (giving you +2 to your primary attribute for casting when concerning spells thus you may get extra spells per day with that), Weapon Focus "ray" (bonus damage with rays), and Improved Initiative (so you act before you are charged .)
Other choices would be either chain spell (hitting more targets with one spell) or Pyromaniac (bonus when setting things on fire)
Any i forgot prerequisites ?
Dougal DeKree, Gnomish Illusionist
[edited to insert feats]