Looking for a party resort
 

Me and 2 buddies will be planning to go to Dominican on Dec 15st and looking to spend below 1000$ for 7 nights..

We are looking for a resort with predominantly americans or canadians and younger age group (19-25)..

We arent really looking for a resort thats quiet at night.. We want alot of bars and good activities to do..

Check out the Riu resorts. They have the best on-site nightlife, including a very popular disco. However, I am not sure you have a realistic budget.

I thought it was pretty realistic as there are plenty of vacations for below 1000$

possibly this page will help you: http://www.resortvacationstogo.com/resort_ticker.html
as you said lots available.
i have never been to an ai so can't help with which ones.
you might look at ai's in or south of cancun. more to do off site like ziplines, caves & cenotes to explore - stuff you and your buds might have fun doing. if this interests you check out: locogringo.com

Check Cancun instead. The Oasis Cancun is well known for it's party atmosphere and Spring Break type crowd. Lots of bars, clubs and entertainment off property also. Very safe to walk around at night and bar hop. In the DR most of the properties have on-site entertainment since it is not advisable to go off site without being on a scheduled tour.

I don't know where you are coming from, but I researched 7 nights out of Houston, TX and it was $1,540.00 for 2 people so if your willing to split the cost it's well be below the $1000 p/p you're looking for.