Ann,
I only know about NYC Leica dealers.
About your lens question: my first and only Leica lens so far is a 50mm summicron f/2 which I use on a .72 M6/ttl. The lens is a recent one (about 2 years old) and is extremely sharp. I've been very happy with its performance with color film, and it is the best lens I've ever used for black and white.
I had a similar question 50mm vs. 35mm and summilux vs. summicron. Although the 50mm will be my prime lens, I do a lot of shooting on the streets of New York. This is where the limitation of the 50mm really shows up. It's very hard to get some of the compositions I want while working in a spontaneous way. The area of coverage is too small. While, I can get closer to the subjects, the result is that I make myself apparent as a photographer. I would say if you're wanting to do street scenes, go with the 35mm. If a wider area of coverage isn't crucial, the 50mm summicron is great.
As to summicron vs. summilux, I'd have to ask whether a little more aperture is worth the additional $800 to $1,000. I think that's the difference between a 50mm summicron and a 50 mm summilux. The f/2 is fast enough for me in most circumstances. You can always use fast films. I've borrowed a friends 35mm summicron f/2 and would recommend it highly. It performs extremely well and is 1/2 the price a a summilux...and it's a lot lighter, which is something to consider as well if you're going to be walking around with it all day.