Adding to your iCloud storage won't give you extra storage on your phone - iCloud storage is for backing up your documents, files, photos etc from your device(s), you can't store music for the Music app in it.
You can subscribe to iTunes Match from your computer's iTunes and upload your music to it from there. But to then be able to play your music you will either need to stream it from Match (in which case you will need an internet connnection), or you will have nee to have downloaded it onto your phone (which if you haven't got enough space on it you won't be able to do).
iTunes Match : http://www.apple.com/itunes/itunes-match/
Depending upon what version of iOS that you have on your phone you might have a Settings > General > Usage which will show how much space each app is taking.
You could also consider changing the file format of those music tracks on your computer's iTunes so that each track takes up less space (though if you go to too low a bit rate you may notice the lower quality) : http://support.apple.com/kb/HT1550