So if you spend $1500 to get 3000 points, you get $25 worth of gas. That's a reward of 1.67%. If you spend $3000 to get 3000 points, that's a reward of 0.83%. Miniscule.

My suggestion to you is to dump that card like an ugly girlfriend and get a Citi Dividends Platinum or an AT&T Universal Cash Rewards. 5% cash back on any purchase made from a gas station, grocery store, or drugstore, and 1% on everything else. There's a $300 yearly reward limit, but you can get two cards of each per household.

EDIT: screwed up the percentage calcs. Fixed