P0171 and Oil Leak

Having problem with my 2009 A3, base model. My engine light came on (which it does periodically, but goes off after a day, always has), this time it stayed on. I ran it in to Auto Zone to run code, got P0171. Went ahead and made apt with Audi, thinking issue maybe still under warranty. (car had 118k miles at the time, yes I drive a lot, about 25k a year). First, I don't like my Audi dealer in my area. Second, they told me code wasn't a big deal, some type of pressure issue, not under warranty, fix when can (at $600 price tag). But they said in their review they found a small oil leak. I had noticed same, but seems I have always had to add oil every now and then anyway, these forums say yeah, Audi. I started paying more attention and sure enough, seeing oil on garage floor, adding a quart about every 2 weeks. My question is, any merit to these additives that you can use that help seal up leaks? Or do I need to skip those and go with the fairly hefty price tag Audi gave me for repairs? I absolutely love this car, but like I said, I do drive a lot, about to start driving more with a kid playing college ball 7 hours away this fall. I can't decide if I keep putting money into it or time to trade.