I highly recommend using the Putty Hill garage. I had an emergency situation come up, and not only did they stay open late to help me, but they went way above and beyond the call of duty to help. I was traveling around the beltway on Christmas Eve with my 2 young kids and my dog(!) and got a flat tire, and was a good 45 minutes from my house and where I was supposed to be. I called at least 8 stations in the area trying to find one open and willing to help at 4pm on Xmas eve. They were closing their shop but agreed to stay to help. I limped the mile or so to the station, and it turns out, my tire was completely blown out. I had no spare and a donut tire that was useless due to its size. They had to fish through their old tires and find an adequate replacement, which they did with expert percission and speed! Within 30 minutes, I was back on the road - and the best part, these good samaritans didn't even charge me for their time spent, staying open late on a holiday, or for the barely-used tire. Don't bother with other stations -- trust these guys to fix your car, do it right the first time, and get it done at a reasonable price.
Thanks guys for your help and compassion - we made it safely to our destination and had a great Christmas!