There are multiple ways to solve this problem.
1. Either get ur site secure by getting a VeriSign certification. Believe me its very easy to do that.....they give u gr8 online help.
2. Tie up with ur service provider to give u payment gateway access. This would not cost u at all. Incase ur service provider does not do that then look for service providers.
3. Go to Paypal.com, they provide this service. They will even help u modifiying ur html. It takes just 10 minutes to modify the site.
Incase ur looking for people to help u in increasing conversion ratios at the site. Please do let me know. I will be of gr8 help....Free of cost.
All the best,