Been offline for a few months just updated but now on 1.7.2 with a launcher (Changed that to magic launcher) but I'm lost the file structure is different (No Bin), and besides I had not updated to 1.6.4 in my absense so don't even have a 1.6.4 jar???? Any help would be appreciated.

Use the default launcher, click Edit Profile, and you'll find an option to set the game to any previous version of the game.

Done, thanks