Need Help choosing strings!

[*Doppleganger*]

So Basically Ive been given a bass guitar by a friend, I play cello and acoustic/electric guitar already, so Im not totally oblivious to string instruments.
The Bass itself has 5 strings, I want to get string that would let me tune in fifths, C G D A (cello tuning) as well as this I want the auxiliary string to be a a low F (a fifth beneath the C so as to reach all notes the average bass would be able to).
I want to know what strings to get and whether this is a good idea?

 

[Levin]

I did this but an octave lower, check out the tension chart on the Kalium Strings (circle K) site and get some in a balanced tension there, it worked fine. 35-45 tension somewhere is pretty standard.