The first way to promote your business would be to have a website. If you don't have a website yet, or if you need to promote your site so that it gains the attention of more target markets, you can check out the services of a BPO service provider, since your company is an outsource provider too, and it may help if an outsourcer who already know the business you are in would be the one to promote your site. You can try OIT2P for that.
Aside from that, you may also try Google Adsense , or the popular sites that lets you put up ads. You may also put up some video ads in Youtube. There are a lot you can do actually.