so I haven't picked up an Ultimate Comic in a while but while i was at my local comic store today i decided to take a look at an issue of ultimate avengers and noticed Black widow was in it. Now I thought She died at the end of Ultimates 2 am I wrong? or is this new Widow someone else? in the issue i never saw her without a mask so I'm not really sure.

I have no idea, but you are correct.  Hawkeye put an arrow between her eyes while she was laid up in the hospital at the end of Ultimates 2.  The Ultimate universe (particularly The Ultimates) have gone so crazy recently, I have no idea what's going on anymore.  I'm going to guess this is a different Widow.

Ultimate Black Widow (Natasha Romanoff) was the first Black Widow and was apart of the Ultimates, she was later found out to be a traitor and was killed in Ultimates 2 by Hawkeye. In Ultimate Avengers, we are introduced to a new Black Widow, named Monica Chang, who is Ultimate Nick Fury's ex-wife.