Are you talking about a banjo head?
If so look here:-
http://www.banjohangout.org/archive/104323
My experience has been that pre-made head/hoop combinations of this size are hard to come by from someone like REMO, and even if you can get one it won't fit inside the tension lugs on the instrument properly.
If it's an old banjo then fitting a replacement vellum is the way to go. Soak it stretch it on, let it dry, then trim off the excess.
When buying a vellum allow an extra 3" to actual diameter to allow for "lapping".
A 10" vellum likely to cost you about £24.
David
And yes, Aquila are the business when it comes to Uke strings.