It's in the database under the title "Heather on the Moor" as one might expect. The source is given as Dan Milner's book, A Bonnie Bunch of Roses. There are two tune files, the first is Dan's tune, the second, I think, is the one Paul Brady recorded and is slightly different. Dan's version is harmonized, in his book, with just three chords (A, D, and E in the key of A major). I'd start like that with your version of the tune and see what you copme up with.