I've tried to work out the same thing and have to say I found it hard to find a sight that gave me much firm detail. The best I've found is a wikipedia sight (I know not everyone trusts them). It seems quite thorough and has a chart to help you establish the correct relationship.
The address is en.wikipedia.org/wiki/cousin
I think you are second cousins.
As I understand it (first) cousins have grandparents in common, second cousins have great grandparents in common etc.
To be 'ONCE removed' would be your dad to his cousin's child because there is one generation dividing them
Hope this helps.
def, second cousins and I think the chart on wiki is the best I have seen. I used it recently to prove my cousins kids and my kids were second cousins, not my cousins kids being second cousins to me.
I think anything past first cousins should just be called "not at all interested cousins"