You will probably have to wait for it on Cydia, or if you really want to redo it, restore to the official v3.1.2 and run blackra1n R3 and then blacksn0w from the install.
Good luck...
i dont need blacksn0w i was just wanting to update my blackra1n to see if it used any less memory or anything of that sort.
i looked in /applications/ and i do not have a blackra1n or blacksn0w.app