1998 Buick Skylark/P0758 and P0442

I just bought this car from a used car dealership with 178,000 miles on it. it used to be a rental car, I got it for very cheap and it is a very nice running car. Except I had it for less than 24 hours and the CE light came on. I take it to Auto Zone and have them check it and I get a P0758 code which means something is wrong in the electrical circuit of shift solenoid B, which makes sense the trans. won't down shift when I stop so I have to manually do so. I take it back to the dealer and they supposedly find a "short" in the circuit and had fixed it, except about a day later it starts not down shifting again but this time the light doesn't come on. So I'm thinking that they just pulled the light bulb out of the dash until it comes back on the following day. I take it back to Auto Zone and have them chek it again and this time it gives me a P0442 code which means something is wrong with the Evap. intake system. Now me, being a single parent Dad with 3 kids has no time, knowledge, or money to fix these myself, needs to know about how much we are talking to have someone else fix these. Do any of you know from expirience about how long and how much something like this costs and where I could have it done? I live in Casper WY.

not really eqipped to give quotes! No warranty from where you bought it? Sounds like a lemon! I'd have the tranny problem checked first before worrying too much about the po442 code!