Im getting a dog!!!!! :) :D?

ok as u no im getting a dog its a shih tzu terrier mix named Roxy 4 my b day i don't no what to do how do i take care of it we might keep it 4 awhile so what if it dies we got it from the spca will it have 2 many problems 4 us to afford im scared help!!!!!!!!!!!!!!!!!!!!!!!!!!! and i don't no what 1 looks like so if u find any pictures please show them to me!