1988 Toyota Corolla randomly stalls every few weeks

I just bought a 1988 Toyota corolla, manual 5 sp., carburetor (not
fuel injected), and at what seems to be about a half tank of gas,
whether this is relevant I am not sure, it loses power quickly and
stalls. At first we thought maybe gas gauge was broken. We left it
sitting for a few hours, then put in more gas, cleaned fuel lines with
carb cleaner and replaced fuel filter. Started and ran great for a few
weeks before doing the same thing again. Has happened three times
since...the last time it was definitely not out of gas,and I was able
to keep restarting and go a bit further over and over until finally
home. I also sometimes smell an odor of gas around the car. It seems
that everyone I know thinks they are a mechanic : ), but no one seems
to be exactly sure of the problem...all have conflicting answers. The
big question is...what could it be that causes it to happen
intermittently, then run great for a few weeks? A vacuum leak, bad
fuel pump, crud in the tank from sitting a long time (could it get
past filter), carb issue? Any ideas would be oh so greatly
appreciated! Thanks a million! Obviously I am surely not a mechanic so
excuse any odd questions...I do however have a feeling that after this
I will be much more educated in the rigors of car repair!

Aimee