It's not expensive or difficult to change out the lockset; you can do it very easily, and you can buy a steel lockset at someplace like Home Depot for less than $20 (brass would cost you more.)
The one tool you will need is a thin long-shaft phillips head screwdriver. It takes a bit of patience to get the pins lined up correctly, but it's really not difficult at all to change a lockset; I do it all the time.