Honestly I would wait a month or so. Since gateway only requires it once now you might get a good deal once that's been out for a while (I managed to pick up a US copy for $10 at a gamestop that had been used for the exploit). The other option (if you just want it for gateway) is find a temp member that has one and ship it off to them to install the 4.5 menu exploit.
I don't really suggest doing this I would get one to keep just in case it messes up or you have to format SysNand... I installed it the other day, it was working, gave me device to a friend to make a mii (I was watching him making sure he didn't do anything stupid) and when I got it back after he made a Mii, the NVRam had been uninstalled and I had to re-install it.