I'm not sure about the colored text part.. but for getting your text, you have to use On *:INPUT:*: for it.
If you already have an input script (mirc only identifys one), then you add this line to the beginning:
aline @<your window> [ $+ $timestamp
$+ ] < $+ $me $+ > $1-
That SHOULD work, if you edit the <your window> part.