In game store

I can rarely open up the store anymore, when I do it just gives me the "Session has expired" page with Galio on it, when I can get in the tabs don't work and just have a rectangular image at the top of the screen, I'm trying to purchase some RP so you guys can make a profit on your awesome game we all love and admire! Please help! I'd like to give back to Riot and get some skins for myself and gift my friends!

EDIT: Is there a way I can maybe just purchase RP through the website? Or do I have to do in through the in game client?