Well, there are folks out there that are fairly good and working up clone recipes after tasting a beer, but that's a bit of a crapshoot. If you can't find that receipt, it sounds like you are in for some experimenting.
I hate to rub salt in your wounds, but you should consider keeping a log book (or folder or drawer, or even pile) where you put your complete recipe down, yourself, as well as any notes about the process. You can also put some money into brewing software that saves such stuff. Even then, I don't depend on the hard drive, and I print out all my recipes and notes for saving.