Audi Problems

I bought my car from someone through this site,
they sold me the car as is without me noticing any
problems and them not telling me of any. A week
later I take it for a oil change found out it had a oil
leak. I never pursued the problem I was told it was
huge but it didnt seem bad just a oil leak I’d have to
add a quart every so many miles wasn’t really a
problem. Later on down the road the car would start
acting funny every time the car got in between hot
and cold and I turned it off it wouldn’t start back up
until it was cold again. I stopped driving it as much
but the last time I went to drive it I heard a pop
under the hood I pulled over and looked under my
hood and I had little to nothing of coolant in the
tank so I pulled back around and shut it off went to
put coolant in my tank and noticed it was coming
out the bottom passenger side I had no idea why.
Didn’t start the car since I went to try to start it and
move it and it wouldn’t do anything so I had it
towed don’t know what could be wrong with it.
I spent $3500 on it and recently got new tires for it
before it started acting funny. It has like 130,000
miles to it. I’m not sure if it’s worth looking into
fixing or parting out at this point? I sent it to a local
shop that works on porshes mainly and the guy
seemed iffy and like he was trying to scam me tried
buying my car off me for $300 lol any insights on
what this may be?