Strengthening Resume

I have an internship this summer at a small investment firm, mostly dealing with retirement planning, a few individual wealth management clients, etc. It isn't ideal, but it was last minute since a guy I had an internship lined up with kind of screwed me over. Anyway, I get a small stipend for the summer, but they have also offered to pay for courses that I take, up to a limit. Are there any good courses/certification/skills you guys recommend I pick up for when I'm interviewing for finance in the fall? I've gotten pretty good at basic Excel and Morningstar but know that there are many more skills I should pick up. Perhaps a Python or more advanced Excel? If you were recruiting, what would you be impressed by?