The answer to you first question is no, we do not currently integrate with paysafecard. As to how much effort it would be to do that, it really depends on how good the API is and what functionality you want to support. Usually just receiving payments is not terribly hard to implement. To get an idea of what is involved you can look at https://docs.blesta.com/display/dev/Payment+Gateways. Additionally you can look at the existing gateways either on our github or in the file system under components components/gateways/. If you want to get a developer to produce this for you or give you a quote, you can find a list here. Each of them are here on the forums and you could send them a PM.
Your second question has a bit easier and more satisfactory of an answer. First, make sure you have a merchant gateway installed (e.g. authorize.net, stripe, etc.). Then when you add an order form at admin/plugin/order/admin_forms/add/ check to enable the merchant gateway and currency you want. After that you customers should be presented with the option to pay with credit card on checkout .