Promotion has complicated my exit plan

I was recently promoted from Associate to VP but aside from the bump in title, am not seeing a huge amount of benefit. I wasn't very happy with my 2009 bonus. My base salary went up 50% (from the lower-end of the Associate scale), but my firm's policy is that the salary increase will offset whatever incentive comp I get for 2010. I work for a tyrant MD who likes to keep his staff invisible while working them around the clock. My responsibilities haven't advanced in any way, but all my co-workers have started hassling me with their grievances, saying that I need to escalate them as VP.

I'm basically quite unhappy with my position and hoping to find another one soon. But today my HR partner suddenly came by (my boss and co-workers were nearby) with a sheet of supplementary clauses that I needed to sign as part of my promotion. Basically my termination notice period went to 3 months from 1 month and some 6-month non-compete clauses were mentioned. I wasn't really in a position to object without rousing suspicions.

On the surface of it, the 3 month notice period would seem to raise the bar of difficulty for a swift exit. I imagine many prospective employers would be turned off by the wait. To be honest, my role isn't super business critical so it's totally unnecessary. I know many sales/trading guys who were gone the day they resigned, I imagine it could be due to compliance or being bought out, but I'm in a quasi-research position myself. But knowing my boss, he will try to milk every last ounce of work out of me when the time comes.

Any advice on how to deal with this setback? Also, would I be automatically entitled to offset the 3-month period with any unused leave?