Personally I wouldn't mess with your resolution to stretch out the sides, especially if you have to lower it in the game menu also for your meters sake. Doing that the animation pixelates more and can get pretty gnarly looking. Besides stretching out the sides just think how long the meter bar will get and the game will appear grossly unperportionate. In reality what would you really be gaining.
I keep my task bar on auto hide all the time. For game play I find auto hiding the task bar and having it pop up and down every time the cursor gets close to the bottom covering the meter can be an annoyance. Since you have all that space on the sides move it out of the way to one of the sides. Those black game side bars come in handy for keeping added items you may like to use like the task bar, note pad, a calculator or CPU/Ram meter etc. out of the way of the game view. Any of these items, with the exception of the Cpu/ram meter, can be minimized on your task bar, popped up for use then re-minimized keeping them out of the way.
All are good suggestions, one has to experiment until you get it set comfortably for your personal use.