OH the PAIN!

I have been experiencing some pain for the past couple months and have decided that it is about time I stop ignoring it and decide to do something about it. My fears, which have successfully squelched my research into this, are finding my saving grace to be too expensive and more of a pain in my wallet then I am currently experiencing in my body. But alas, I have reach the point where I'll do just about anything to alleviate some of it. So, I thought I might invoke my "bloggy friendship favors" and ask your advice to see if I might find some relief!
Most of you know that I work from home. Since increasing the amount of hours (I went from 9-3 with an hour lunch to 9-5 with an hour lunch and on the days when I have lots to do, 8-5) No complaints on more hours from me, this means more money, which means hopefully soon, my husband will have the chance to be able to quite his part time job completely and be FULL time as Pastor!! Anyway....moving on......since I have been putting more hours in, naturally I have been sitting at my desk more. I recently upgraded my computer monitor to a size 22 inch (it helps TREMENDOUSLY with my work load and ease of data entry!!) And, due to a new monitor, I switched to a new keyboard and mouse as well. (I have a laptop so it was a little necessary for those) I spent a little extra for the mouse pad and keyboard wrist dealy thing (no idea what they are called) and they have helped a little but due to the height of my desk and the height of my chair, I have been straining my right arm and should and back muscles as I keep my right hand on my mouse for most of the day. Now......a couple things.....I understand my posture is not generally the best (it is best when I am exercising regularly....my core muscles really support me!) But I am wondering if JUST working on my posture will be enough?! Do you think maybe my desk is TOO high?! Is it just my posture?! Have any of you experienced these issues when working at a desk for long periods of time?! Here are a couple pictures just to give you an idea of what I am talking about....

*WARNING*
PLEASE EXCUSE THE MESSY-NESS OF THE DESK! (the office really hasn't been "decorated", we're sticking with "functional" for right now :) )

Picture #1 is "slouchy"

Picture #2 is sitting up straight