Hi Ogre
First of all pat yourself on the back for being able to read the dots.
There is plenty of software available now that can read Midi files, analyse them, change key and let you print off sheet music with chord symbols and lyrics - so you don't need to buy a 101 song book to get 1 song - just find the midi file.
If you want to try one such software package you can get a free downloadable trial version of Midi Connections Lite at http://www.bck.co.uk.
John