Payment Gateway Integration for Online Shop

I need a payment gateway integrated into my online shop. You can check my website here: http://snatchofficial.com (must be http, not https).

Requirements:
- Payment gateways: PayPal, Credit Card, Klarna
- Shopping cart, billing page, address page, and all necessary shop features
- Billing page should include:
- Order summary
- Discount code input
- Billing address form

Support for multiple currencies is uncertain.

Ideal Skills and Experience:
- Experience in integrating multiple payment gateways
- Familiarity with building shopping carts and billing pages
- Strong web development skills, especially with non-secure http sites