Unable to change iTunes region/country

So my friend from canada sent me a 15 dollar itunes card. Unfortunately it can only be redeemed in the canadian store, so i switched my store to canada. I went a ahead and bough 11.49 worths of stuff. and now i am left with 3.51. I cant change my store because I need to spend my balance, and nothing is worth exactly 3.51. I cant add my credit card because its an US card and dosnt work in the canadian store. i need to switch back to US store. Help me, Im stuck between a rock and a hard place.