Last Contribution Date and Amount for a widget

We're looking to further refine our LYBNT dashboard- we're trying to pull in the date of their last contribution and the amount of that last contribution. The closest thing we could find is 'Last Activity Date', but we're not sure what that means- is that the latest contribution date? Or simply the last time that Constituent's record was updated in some fashion?

My brain wants to try something like 

IF ( MAX (Days in Contribution Date) = (Last Activity Date) , (Contribution Amount) , 0 ), but the formula box didn't like that. The box wants the entity after ' = ' to be a value, not another measure, I think.

How would this best be pulled in Analytics? We're working with lists in the meantime, which is doable, but I'd want this process through Analytics if at all possible.