line of least resistance - you need to install the TTS1. open the midi files in RealBand and then render them as mp3s. then transfer them to an ipod touch with a playlist for each song so that the ipod does not play all the mp3s sequentially.

the sound quality depends on the synth you are using - the TTS1 uses roland sounds so as mp3s they should sound similar to what your hardware player did.

second line of least resistance install the TTS1 and play your midis in RealBand.

but i'd sooner trust an ipod than a laptop playing live and you can buy a backup ipod on ebay for a few pounds/dollars