If I understand correctly, you are a marketing company, offering branding type services or sales/marekting coaching. I can offer some pretty good advice here, as I know first hand what works for getting these types of leads...for ourselves...we are also a marketing company. I`m not sure if it would be easier or harder for your specific type of marketing though...
Telemarketing - if you do this, be weary. Telemarketing leads can be very good, set appointments, but they can get costly. My experience with telemarketing is that for every 100 companies that say they can generate results...1 or 2 do - the other leave you wanting your money back. Most people would charge $75-100 for every appointment, I know a company that does it for $50. Costs can add up quick, if you`re not closing.
Email marketing - you can get these types of leads for $30 at pretty good quality.
PPC - around $30
Affiliate networks if you brand yourself properly - $15-25/lead, but with some quality issues.
Personally I always recommend a combination until you find the best fit for you, but it depends on your budget.
One thing I would suggest is don`t hire someone on an hourly fee - I hear so many promises in this field, if people truly are confident that they can produce results, then they should put their money where their mouth is. Marketing leads aren`t the easiest. When we were starting out, we were screwed many times by lead generation companies that at their hourly rate led to a lead costing us infinity dollars - as in, they didn`t generate any.
Chris Nicholl
nvamarketing.com