If i was to back the game now as a gold donor would i get any new/future rewards such as those added with steam early access packs or something else. Or is it just the few things that come with gold?

Yes, you will receive any future expansions to your highest reward tier as well as future expansions to the reward tiers below it. We're currently working on the tech to expand the rewards layout to show more details. This will also include details regarding the reward's travel power and a visualization of the reward's special cape.

How much longer are the current rewards going to be available? The reason i ask is due to the fact I have to wait for my orcs must die unchained refund.

Also is it possible to donate with anything other than paypal? All i have is a visa

The crowdfunding campaign will remain live until the Steam launch begins. We'll announce the Steam launch date once we are absolutely sure about the launch. At that point we will inform the community as to when the campaign will end. That is as much as we can say at this moment.

PayPal is our only payment gateway at the moment. However, PayPal does have a feature of its account system which allows members to pay directly with a credit/debit card.