Maybe, I'm mis-understanding the term "Cold Calling". Are you taking about calling from a general list of phone numbers of those wanting real estate information or just pulling a page out of the phone-book and working your way down?
I own a telemarketing firm. I don't do real estate, but have for about 500 or so clients in the past. I don't do it because the call campaigns are too small and very time consuming. Though they are very successful and I would say it is well worth the investment if you can afford it.
The quote they gave you seems to be a little high - but the figures sound about right on the money.
With FSBO campaigns I would book 7 to 8 appointments per hour - per agent. Because the connection ratio was high I could only dial about 30 dials an hour.
With Expireds I would book about 4 appointments per hour per caller.
Both of the above campaigns resulted in a 10% listing ratio for the "GOOD" agents I called for. The bad ones still listed, but they sucked.
With straight cold calling the appointment conversion was around the 2% mark. I would make 100 dials an hour (predictive dialer), speak with ten live people and book two of them for an appointment. A bad day would be 1%.
Hope this helps...it's well worth it once you know how to work these types of leads.