i think you're forgeted. unless you can install RGSC (which i think you're using?) onto an external HDD and take that someplace with a computer & good internet, i think you're gonna have to wait. well, unless you have someone w/ good ass internet buy a big flash drive, download GTAV onto it, and mail it to you. either way, you're looking at some convoluted stuff.
I have a 64GB flash drive
it's absurd but boy has it all of a sudden become very useful
what I'm thinking about right now is downloading it at my dad's using my laptop, and sticking it on that flash drive, then moving it to my desktop later
the only thing I'm really worried about is whether or not the launcher will actually let me install the game onto a flash drive. if it doesn't, then idk what I'll do, cus I absolutely do not have room for it on my laptop, lol