Well that picture gives a totally new context to what you might be wanting to do. Initially I thought you only had a bike frame. Which I'd build out with a more modern 11 or even 12 speed group.

For starters, are you wanting to keep the existing components? Do they seem in good condition?

To pick a crank, it'd help to know what RD that is. Not just the name of the series but the actual part number. If Shimano, that likely is stamped on the back side of the parallelogram. Or at lest how many sprockets are on the rear. And you have confirmed that's a 2x front shifter? It'd be better to pull up the hood and get the part number off the body of the STI or multifunction lever if another brand.