There are several Gallifreyan fonts out there (WS Simple Gallifreyan is the most popular and widely-used, and available at all good font sites) but it's actually ridiculously simple to make your own if you have some imagination and some kind of drawing tool on your computer. Nothing fancy, in fact MS Paint would do the job nicely. Just click on the 'circle tool' and let your typographic fancy flow free.
This was my effort (using GIMP) after just under an hour's work. The thing that took the most time was imagining what the symbols would look like.
It does't mean anything - it's purely decorative - but it does look worthy of Rassilon himself. If you're really ambitious you could come up with your own alphabet for it. I don't have that kind of...time.