I just changed my screen and digitizer together because of the same issue (water damage). I recommend changing both the screen and digitizer assembly together because just replacing the digitizer can be very tricky. Watch this video for reference
http://youtu.be/A1ntOfJS_1c?list=UUdCZPlI8G7KL3M6dNYk6qpA
I bought the screen and digitizer for $185 and it took me a total of 45 mins to 1 hr to replace. Bought the assembly off of ebay
http://www.ebay.com/sch/i.html?_from=R40&_trksid=p2050601.m570.l1313.TR2.TRC0.A0.H0.Xnote+3+screen+and+digitizer&_nkw=note+3+screen+and+digitizer&_sacat=0
'''NOTE:''' I had to re- bend the home button spring clips (on back of main board) on mine and make sure that all the flex cables snapped into the main board because this results in the phone malfunctioning (aka the finger swiping not working on the new screen but S-Pen worked). I had to unclip and reclip the screen cable 3 times before I got it in correct.
TRUST ME IT WASN'T HARD JUST TAKES PATIENCE