Little help?

Hey,
Was wondering if anyone knew where i could get a decent hand calculator for Omaha High. Have just started playing a lot of Pot limit tourneys and, whilst doing well in the early levels, i get to the final table and am quickly gone.
Have what I think are good drawing hands but am often faced with players dumping a huge bet post flop when they get a set. Any advice? Am hesitant throwing 30-50% of my stack at a hand when I'm still drawing.