Hey Lutz,
I haven't followed these posts in a while, but I understand your frustation. I was there. And, I was about to lose it all! But... all you can do is let go. Your trackpad, like all of ours (mine included), needs to be replaced. That's it. You're life will be so much more peaceful again after that happens. I'm convinced there is no other fix. Apple messed up, and messed up bad, but you just need to let go and accept that you have to take your computer in and have the trackpad replaced. Nothing else is going to solve it. Period. Is that a proper response to all of this from Apple? **** no! But...****..what can we do here? I would love to boycott Apple for crap like this, but they clearly won't listen, and I've used the alternatives for forever. And...in my heart of hearts, I know that when my Mac is working...it's INFINITELY better than anything else I've ever used.
Like you, I am new to Apple and this is honestly my very first Mac (or even Apple product in general). I totally lost it after this happened to me, and now that my machine is working again, I'm pretty freakin' happy, honestly. Is this excusable? Absolutely not. But, again, I'm not sure what the other option is?
On the plus of all of this, I finally took my Mac into the Genius bar...or whatever BS they call that place is. And, they told me it would be 5 days. Fine...I was expecting that. They called me back the SAME afternoon! I've been there one other time for an unrelated issue, and I must say, I'm pretty impressed with what they've done with the Genius bar.
Anyway, looks like we got our MBAs around the same time, so count yourself fortunate that it's taken this long for your trackpad to crash out. I've been using my new, replaced, trackpad for almost 5 months now, and it's a gem. If it craps out again...well, I may retract this whole reply! But...I've honestly been pretty happy with the service, and while completel frustrated in the same regard, I've realized the only thing I can personal do is let go and hope for the best.
Use a USB mouse in the meantime, and take that thing in as soon as possible! I promise, there is no other answer, as big of a bummer as it is to hear that, but you need that trackpad replaced. Period. I spent 2 months trying to find another fix. There is none. Don't waste your time. Take it in and get it over with.