S.,
It really stinks being a working mom, huh? I am probably a rare women who actually didn't mind pumping at work. First off, a hands free pumping bra is a must in my opinion. I liked the one that was a bustier more than an actual bra, because they are expensive and I didn't want to have to wear it all day. The bustier I am able to zip on and off at each pumping session, and I have two of them so I can wash one and still have one to take with me.
I also think a good electric pump is a must. I have the Medela InStyle - the bag is stylish but fairly unobtrusive, so it doesn't scream to my co-workers - PUMPING! LOL I also like that it comes with a battery pack (that works great) and you can buy a car plug for your lighter jack. A good pump makes pumping time far more efficient.
My company provided a private room with a comfortable chair and soft light. But what I really enjoyed most was the "me" time. Sometimes I read, and sometimes I take my laptop in with me and watch DVDs on it.
The DVDs were especially great when I was pumping 3x a day - I could see almost an entire movie, depending on the length, and because I was using my laptop, I could also keep up with email and such. Even a small portable DVD player would do the trick.
It was a little bit of peace and quiet in my chaotic life.
I have also pumped in the car, although I have a standard transmission, so it wasn't easy and sometimes the pump would dislodge and I'd end up soaked.
To start, pump at least as many times as your baby would eat if you were home. After a while, you can probably adjust (usually decrease) to the number of bottles the baby takes in day or the number of ounces.
I am in the weaning process, and down to pumping once a day, but I am already missing that quiet time.
I'd be happy to answer any specific questions, if you have them - email me off line.
Good luck!
C.