1.8t sport with various problems!

Hi guys!

Ive just bought an A3 sport on ebay for a song at £430 obviously with various problems which im attempting to tackle. My main concern is the speedo isnt working which i know is a known fault, i've bought a speed sensor on ebay although from doing research its the wrong one (Even though on ebay it shows the model is correct) http://www.ebay.co.uk/itm/171351280312?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649 so i just want to double check which one i need and the location of it on the engine/ gearbox.

Ive hooked it up to a vagcom and have these codes flashing up:

00562: Sensor for oil level/temperature G266 open or short to B+

01423: Lateral Acceleration sensor (g200) 

16486: MAF G70 Signal too low

16514: Oxygen (Lambda) sensor B1 S1 malfunction in circuit

16804: Catalyst system Bank 1 Efficiency below threshold

16885:Vehicle Speed Sensor G22 Implausable signal

17545: Fuel trim Bank 1 (add) System too rich

17705: Pressure drop between turbo and throttle valve (Check DV)

The car runs fine at the moment although the idle is a little lumpy and does feel a little underpowered, and the fuel gauge is up and down which i understand can be down to the speedo and the temperature gauge isnt reading correctly.

I know these codes and solutions have probably been posted many times and i am slowly working my way through to see if i can find out myself but any help would be greatly appreciated as its a car i would love to have running properly so i can enjoy it fully!
Thanks,

Brett