How can I get a flat stomach in 3-4 weeks?

I'm already pretty slim, but i have small pudge/love handles and school lets out in 3 weeks so I'd really like to tone my stomach up before then. The past two weeks I've been doing 100 crunches in the morning and 100 crunches at night and then briskly walking/jogging 1 mile atleast 4-5 times a week. What else can I do?