The rear of my 4x4 is leaking ...

I've got a used Toyota Land Cruiser Mark II that I've been wanting to touch up.  I have been having problems with this leak in the rear of my 4x4 for the past year.  It looks like it's leaking through a small gap between the rear door and the body.  Maybe the inline rubber seal has come undone but I have yet to check it out.  Yeah for about a year now, but i'm sure Los Angeles auto repair wouldn't have any problem fixing this up.  If only I had an auto mechanic hands i probably be able do it myself.  i know how to change my oil and change a tire and this probably i would know too it's just that laziness sometimes creeps in.  I once had my head gasket give out on me while driving an older car.  Not cool at all, found out the motor oil was like close to empty.  Told my dad to check it out before driving, but i'm not blaming him for it.. it's my car i should've checked it earlier, right?  So i've never really owned a Brand New Car before.  Maybe it's time for me to get one, a Honda Civic looks cool.  Sleek body, and cool features.