My 1957 Oval is coming home

Three years ago I posted this:

http://tinyurl.com/nd9ts

Recap: 1957 Beetle sitting in West Texas - bought it. Then it sat in
W. Texas at a friend's house for 3 years. I'm finally moving it into
my garage in a couple of weeks, and am anxious to get started on it.

Here are a few pictures:

http://flickr.com/photos/rhino72/149...n/photostream/
http://flickr.com/photos/rhino72/149...n/photostream/
http://flickr.com/photos/rhino72/149...n/photostream/
http://flickr.com/photos/rhino72/149...n/photostream/

It has the original 36hp motor. I can turn the motor over by hand, so
it isn't locked up - aside from that, I have no clue if it'll run, or
how worn it is. The pan is very clean. The front and rear look
pristine (no evidence whatsoever of any collision damage). Surface
rust here and there on body, but no rust-through that I could find,
even on corners and crevices. Interior is pretty rough. It's missing
the back seat. Channels are solid. Overall it's pretty dusty/dirty.
I ended up paying $200.

I don't know how the project will go. I'm partial to original
restorations over custom. I'd like to drive it to work occasionally,
but realize it will be a lot of work to get it ready. I think I'm just
going to jump in and see what happens.

I have thought about crating the 36hp in favor of a dual port 1600 I
have stashed, to save the original motor from excess wear, and to boost
the power a bit, since I don't plan on keeping this garaged. I want to
eventially drive it a fair amount. Any advise on motor choice?

How about brakes? Upgrade during the process of getting it
running/driving? Keep it 6V? I hope these questions don't seem too
sacriligious.

How much is another back seat going to cost me? Are they hard to find?

Thanks for any advice - James

Any idea on a reasonable price for a back seat for this car? Are they
(correctly) interchangeable with later models?

Thanks