My gramma won't let me get a 10 gallon?

My tank is way too small for the fish I have. I'm not going to tell you what fish i have and what size. All you 'fish maniacs' will go into conniptions. So anyway, I'm trying to let her get me a ten gallon but I just got the 'tank' a month ago and she says I have to wait at LEAST a year. Translation: 6 months. The fish are gonna die in six months in that size tank. Also, it wasn;t my idea to cram all these in a small tank, my grandma said I could only get fish if she picks them out. So yeah. Not my fault. I was planning on getting a betta and an african dwarf but nooo... What do I do?