my advice on the clothes thing would be to get some forgiving inexpensive clothing. An elastic-waisted jersey skirt, for example -- I'm still wearing one that I bought 20 lbs ago, and it still looks fine; it just rides at my hips now instead of at my waist. This is really the kind of thing that clothes like that are made for, and you can usually find them in professional-enough varities for the office, even if your office is pretty conservative.

Plus, no one notices if you wear a (say) plain black a-line skirt three days out of five, so you can get a LOT of wear out of just a few pieces. I wear my skirts about 5-6 times between washings, as long as I haven't gotten anything on them. All they need is an airing-out inbetween and maybe a blast of steam from the steam iron (no iron, just steam).

another option is having your existing clothes altered. Much cheaper than replacing, especially if you have some good-quality pieces you'd like to keep! I've saved some really nice items that way as I've lost weight.