Big Tim, you'll have to look at some of the other threads on Carrickfergus, as they were supplied in one or another of the Origin discussions of this song.

I'm no expert on Irish, but in Scottish Gaelic, it would seem to say literally:

And will make long from place this town Cuain.

In more colloquial English, And time will make from this place, the town of Cuain

Hopefully Phillipa or one of the Irish folk can be more accurate.