My comment still applies. 11.3 patched out DSiWare downgrade by adding a NATIVE_FIRM requirement to the homemenu. This has rendered DSiWare downgrade completely useless because you can't apply the 10.4 FIRM. So even if they could download the games, they can't use it to downgrade the system.
So basically, they need a hardmod to restore the previous NAND. If they don't have a hardmod, then they are shit out of luck until one of these things happens;
1: They get a hardmod done
2: A new exploit is found
3: Sell the system and buy a new one that can be exploited.
This isn't me being mean. The OP should have done some research before updating. It's been well documented that Gateway lacks FIRM0/1 protection and also documented that 11.3 won't even boot with the Gateway because it's using an older NATIVE_FIRM. Basically the OP was fucked no matter what they were doing and it was because of they failed to do any form of research before hand.