It`s very frustrating when you want to rehome more animals, yet can`t scource them locally. Look on ad trader (just google ad trader and the page should come up!)
There may be a Northern Irelend equivellant, but I`m not sure. Online free-ads are usually chock a block with animals looking for homes sadly. If I see anything, I`ll contact you!
Don`t give up. x
Edited: I googled `hamster breeders in northern ireland` and came up with a fair few breeders and clubs!
http://www.angelfire.com/biz/RadioHams/
They are based in Lisburn, south of Belfast N.Ireland
Also, you could try the Northern Ireland Hamster Club for contacts?
Also, you could ask babyboos (member on here!) if she is travelling to Northern Ireland this year?
You could also try your own animal welfare organisation?