I wouldn't do economics, there are HORDES of econ students out there, and it's hard to get noticed. If I were you I'd finish the accounting but look into a minor. Math/statistics minor along with accounting could set you up for some nice positions in the future, and it'll help you stand out amongst a crowd of applicants (at least, more than just an econ degree would).
Other good option IMO would be programming, maybe look at a computer science minor.
As far as sticking within a BA in bidness, what are your other options? Are all 10 classes within the business school program?