I'm all the way across the continent, so I can't really offer my services in good conscience, but there's a demo you can play with here:
http://www.vicidial.org/demo.php along with a live CD you can install on whatever old computer you have lying around your office. You'll find it has all the goodies of major proprietary systems and then some, it's very flexible and capable of integrating with external solutions easily for those few things it can't do itself. The only con really is the esthetics, but the 6 digits savings you'll be making in license fees adequately compensates for the lack of trivial eye candy.
Also, I'd be careful about visiting 3rd party call centers: Those guys are sharks, they'll likely use it as an opportunity to convince you to outsource all your business to them XD Good luck!