Affiliate Marketing Secrets

I work for a company who is launching a new product, and we can’t find any sort of basis for figuring out how much we need to spend… Like do we need to do 100 grand in advertising several times in different magazines, and 40k in radio advertising? Or should we just spend a few thousand dollars here and there on a few niche ads?
I know it depends a lot on the product, but it is a completely new product to market (something different than anything else out there).
How do we determine how much advertising we really need to do?
We just met with 3 ad firms who all said the same thing- “we don’t tell you how much, just what and where” is pretty much what I’ve gotten.That was my answer to our dillemma, which didn’t help.