Alper this "started to heat around the top of the tablet." is a pretty good indication that you have something shortening out or already failed. You do have to take care of the water damage first.
For now you want to stop continuing to try to charge, sync or otherwise use your tablet. This potentially can make a bad situation worse since it may further damage your phone.
The next thing to do is to clean it. Disassemble your tablet using something like [https://www.youtube.com/watch?v=6y2u62EmAjQ|this video] You must remove all EMI shields. If you do not remove those, you might as well not do anything. After you remove those, clean all the boards, connectors etc., +96% isopropyl alcohol. Isopropyl alcohol in the higher concentration will evaporate quickly and there will be no reason to wait for any drying. Follow [guide|5825|this guide] , and even so it was written for an Apple iPhone 3G, all the points are still pertinent to your tablet. If you have to use water to remove any gross contamination, use sterile water and not drinking water. The importance here is the cleaning. While you clean your board, check for any obvious damage, like burned or missing components etc. All these steps are to avoid delayed failure caused by corrosion. Best thing to do would be to clean it with an ultrasonic cleaner, but if you do not have access to one, this will at least help. Once all this is done, change your battery and reassemble your tablet and reevaluate. Until it is cleaned, everything will only be a guess. Even with all this, water damage has only a small chance to be fully repaired, but at least you can give it a try.