staying under $700 will not be easy, you can get a stereo for under $200 but good speakers can get expensive. dash speakers (kappa 462.9cfp) are about $130 a pair, rollbar speakers (Kappa 52.9i) are about $130 a pair and a pyle plbass10 low profile amp sub is about $110 each, if you use crutchfield they have the wrong info for the front dash speakers, mine are 2 way 4x6 plate speakers, they will only recommend a 4" round for the dash which will work but is not same as factory. if you use 2 subs that should put you at about $700 with the stuff i listed above
i would recomend you start at crutchfield.com, thers are so many options when it comes to radios, like bluetooth, HD, ect..... but i would check into the infinity reference 6432cfp or infinity kappa 462.9cfp for the front dash. jeep considers these as 4 of the 7 speakers, at least on my year and model. these will match the factory set up, as far as the roll bar you have many options but you may want to stay with the kappa or reference models, the only way to get a speaker that will fit in the subwoofer box with out modification is thru jeep, i had no luck finding 6 3/4 subwoofer. you can also go with a pyle or boss amplified low profile subwoofer and mount them on tailgate or under front seats. also you might want to look into marine certified stereos and speakers so you don't have to worry about them getting damp again.