Having just gone through what you are experiencing, I can tell you that unless you are very fortunate, your "favorite local auto parts store" WON'T have the pigtail you are looking for--neither will your local transmission shop.
Try "700r4 connector pigtail" as your search term on evilbay and you should find one for less than $9.
BTW, you will find that there are 3 major valve body configurations and plus enough internal wiring combinations to drive you crazy. The least expensive alternative is if you have a functional #13 valve. Then you just have to replace that and place a suitable valve ball on the top of your solenoid and you don't even need to have the external wiring. I was not, however, so lucky.
So...I now have my Lokar TV cable installed and set and my new pigtail installed with plans to wire it to a hot to check out the lockup and then hopefully wire it to a transmission pressure switch for my 4th gear lockup.
If I were you, after locating a pigtail, I'd get a good transmission guy involved to make sure your TV cable is set and your lockup system is installed and working correctly.
