2007 Aveo - bought used - maintenance questions

[jaydoc]

Hi all, first post on these forums.

I just got an used Aveo 2007 LS, my first car ever. Since I got the car from a friend who has already moved overseas, I don't know much about how the car was maintained. I only know the following from the documents he left in the car when he sold it to me.

---Tires (2, don't know which!) changed, thrust alignment, wheel bearing play checked 3/13 - 110000 miles.
---A/C compressor, Front disc brake rotors and pans were replaced in 4/13 - 114000 miles
---Crankshaft sensor, MAP sensor replaced and oil changed in 6/13 - 118000 miles

When I got the car it had 120000 miles on it and nothing had been done since 6/13. About a month after I got it I had to replace the battery and the alternator which both died while I was on the highway a week ago. Total cost for the towing and services came up to $600 and I only paid $2500 for the car itself!

It also has the check engine light on and its from a faulty cam shank position sensor that needs to replaced according to the mechanic who did the other repairs. It costs $200 to get it done apparently.

My questions are

1. Should I get the cam shank sensor replaced right now? Or can I wait until I take it for a scheduled maintenance visit?
2. Where should I go for the regular maintenance? I don't know which dealer he got it from. Can I just go to my local neighborhood auto repair shop?
3. And HOW much "maintenance" should I have done on it? Seeing as I paid only $2500 for the car, I somehow don't feel like paying a grand just to have it "checked" out! But again, this is my first car, and I am no good at judging these things.

I want to act like I know something about stuff like this when I speak to the mechanics that will be doing it, so please help me out, guys.

Thanks a lot.