Better Golf Clubs?

Went to the driving range with a girlfriend this morning.... Saw that she could hit quite well. Looked at her set of clubs. It was of the same brand as mine, but of a different model. Thought to myself...."is she really good or could it be that her clubs are better?". Well, you see...when I bought my clubs, I chose the CHEAPEST set that was available, which means that it is also the most basic set. Now, I'm thinking if I should have bought something better. Maybe I'll change to a set of Callaway irons in a couple of months. As for the driver, wonder if I could use H's Big Bertha.