If you are in a hurry, get a sky just to play (or buy some retail in a sale idk xD sky is very pricely x3x at least here)
Gateway already show us it working on a n3DS( the "lite" version, not the XL but don't must be very different ...), but they released nothing yet , their 3.0 version is a "instable beta" because there aren't public support for new 3DS, the only newa bout that they said is that they are having problem wih 9.5 compatibility emunand there(or something like this õ3o) because some n3DS features. WEll I think they will do it, you can wait if you aren't in a hurry, maybe another good card come on this time.
About playing DS/GBA games there ... their card blue is blocked on 6.x up systens, not sure if they can update it do make work, but on a 3DS there are a way (that I was asking for help as you can see above ...) , gba would be emulation there(Ds cart) , cia mod or homebrew emulation, not sure if i'ts perfect in some way :v
I'm not sure , but I think R4i Gold PRO and R4i RTS Dual-core