Sure sounds like the starter to me.  I have these in Bosch rebuilt for $140
with a $15 core charge (this is the same unit that the dealer is going to try
to sell you for $240).

However before you try the expensive stuff you may want to try your ignition
switch as this can cause a similar problem.  These are only $9 and you can
test this very easily.  Just remove the bottom cover on your steering wheel
housing.  Unplug the ignition switch plug from your old switch and plug it
into the new one.  You only have to use a screw driver to get it started and
just leave it hanging down while you are driving, etc until you see wether
the problem repeats itself or not.  If the problem comes back then it is the
starter and you only spent $9 trying to figure this out.  If it doesn't come
back then it was the switch all along and now you just have to install it
(see instructions on the "Ask Ken" page on my website.
Hope this helps.

Thanks,
Ken Wilford
http://www.vanagain.com
John 3:16
Phone: (856)-765-1583
Shop:   (856)-327-0027
Fax:     (856)-327-2242