I suggest that you stop and re-evaluate what you are trying to accomplish. It sounds like you are trying to help the school. To kick this off I strongly suggest that you look into renting and after discussing what you want with a few rental shops, and then standing back up after they give you a price, they can explain what you can get within your budget.
Anything that fits in your car won't work well in a field. A backyard party where you only have to cover 50 feet with medium volume music and no requirement for deep bass is simple and can be covered with a small bar system. However, if you want serious music power and bass you can feel (aka a prom system) outdoors you probably need at least 4x what you think you need. It would basically be 2x of a prom system. As Canute said, you are talking about a live sound setup, not a simple DJ rig. Hopefully there is a hard structure where you will setup, preferably backed against a building which has lots of electrical power. If you are against a building you at least have a chance of using it to reflect bass energy.
There is no way this will fit in a car. You would be lucky to get it into a van! Talk to the rental people and see what they can provide within your budget and have them deliver it. I would expect at least 6,000 real world watts total power to be the starting point. 1,000 watts to each sub driver 2x duals means 4,000 for subs and then at least 1,000 to each top. This is EV QRX, JBL SRX territory. Peavey QW would be bottom of the barrel for outdoors. So, if we're talking 6,000 watts of musical power, you should plan on about the same in generator power requirement. That's a big loud generator. (The nice quiet Hondas top out at 2,000 watts, but if you get the proper setup you can pair them to provide 4,000 watts quietly, but expensively.)
If the budget is less than $1,000 I'd suggest that you give up on low bass and forgot about subs. Concentrate on decent tops that are highly efficient and be happy with that.
