You will need to buy a skin head and mount it. They are available from several places including Elderly Instruments (www.elderly.com). The skin head will be considerably larger than you need, but it can easily be trimmed. Mounting a skin head is a bit of a production; not difficult, but it requires some patience.
I wouldn't recommend the heads you'll find on Elderly Instruments, I put those on my banjo and they were disgusting: hairy, stinky and ugly. I got the heads I'm currently using on Clifford Essex (from the UK). Or you can just use the stupid cat skin: http://turnandbank.com/wp-content/uploads/2011/04/P1210822.jpg
I am a professional leather craftsman (among other things) I have two banjo ukes which are mounted just like yours. I used drum heads. I will sell you one for $12.00. For some strange reason they are cheaper to buy them a dozen at a time than to just buy two singles. They are not at all difficult to put on. If you want to do it, I will give you a step by step set of instructions of how to do it. you can ask as many questions as you need about doing it. I have local long distance calling, so I can call you at your convenience and talk to you in realtime about what you are doing