Question: Ok, long story short, I'm currious how long it would take an agency to crack a 10-15 character winrar password. The file names in the archive are also scrambled including a word at the start and numbers and characters. Roughly, should I have reason to believe this could be cracked within a reasonable time frame?

Answer: 
The answer is 42 of course.

In all seriousness, this question is unanswerable. There are many factors, including but not limited to the amount of hardware the attacker is willing to throw at you.

Your password is **weak** though, it's very predictable which is the bane of strong passwords.
As mentioned rar uses SHA-1 which is pretty strong. You can have a good comparison of different algorithms [here](http://www.gat3way.eu/index.php?mact=News,cntnt01,detail,0&cntnt01articleid=192&cntnt01returnid=15).
As you can see cracking rar is slower than WPA-PSK.