A friend of mine once played a blasting sorceress with great success. Sure, battlefield control is better than blasting, but after all death is the ultimate debuff, and the ability to pound 1000+ damage straight into the face of your enemy tends to help you achieve exactly that.
First, your DM has severely limited your book selection. Im not going to dig too far into what you are missing, but lets just say that you would have wanted the War Mage prestige class, the Dalamars Lightning Lance spell and the Reserves of Strength feat from the dragonlance books. Moving on.
Second, realize that metamagic is your friend. Get either the Rapid Metamagic ACF from PHB2 instead of your ability to summon a familiar, or get the Rapid Metamagic feat from Complete Something (Mage or Arcane) ASAP. Then proceed to get Metamagic Feats such as Empower Spell, Quicken Spell, Arcane Thesis (Scorching Ray), Metamagic School Focus (Evocation), Energy Substitution (Cold), Energy Admixture, and Chain Spell. The idea is, of course, that you use the 2nd level spell Scorching Ray as your primary blasting tool, and use metamagic cost reducers to pile on more and more metamagic effects that will your damage output. As Scorching Ray is a fire spell, you will often encounter creatures immune to it in its basic form, but that is what you have Energy Substitution (Cold) for, as most creatures that is immune to fire damage are fire subtypes, who will take double damage from cold damage.
The most significant advantage of using Sorrching Ray as your only blasting tool, is that you don't have to take blasting spells of higher levels, and instead have the option of taking more battlefield control, utility and buff/debuff to help you be a better rounded caster. After all, the most important aspect in playing a blaster is to be able to do everything else too, which is why warmages fail so bad.