I think you will find plenty of answers to this question if you do a search. I think answers vary from before, after, and seperate. I would suggest a clean diet, 3-4 days of weight training and cardio seperated by 4-8 hours on training days, or on seperate days. It sounds to me that you are, at least right now, focusing on some fat loss (probably for summer ) Keep a decent level of protien intake and up your cardio a bit until you reach your desired "look" and return to your normal routine. For me, I currently do Mon, Tues, Thurs, Fri - training at 5:00PM, Tues, Thur, Sat - HIIT at noon.
Cardio catabolizes muscle. If you do extra cardio to burn the fat you'll lose muscle mass. You could try circuit training or super sets to add additional caloric burn to your weigh training routine.
My suggestion: Lose the fat through a clean diet and a good cardio program. You can sort of call this "wiping clean the slate" - you'll have a lean, clean body to work with and build muscle with.
If you have to do both in the same session, do weights first, knock back a protein shake with 20g of protein, then hit the cardio machines. But ideally to minimize muscle catabolism, do cardio and weights on separate days, or 4+ hours apart.