You're already good as it is. And that should last you a year at least. Save up, it's not necessary. Unless you went and got a 24" monitor or something.
*edit*
I see you're after Grievearz steal of a deal. In that case, go for it, because at $190, it's hard to pass up. You just have to sell the board. And if you're looking for an SLI board that's not expensive, I hear the popular choice, is the EVGA 750i FTW.