You should be able to still use the TGC account log on for the store.
Log into the store front first, then try the download from store option and see if it will update your stuff.
Let me know how this goes for you.
Intel(R) Core(TM)2 Quad CPU Q6600 @ 2.40GHz, 2400 Mhz, 4 Core(s), 4 Logical Processor(s), 8gb RAM, Nvidia gtx660, Windows 7 Pro 64bit