First of all, you could re-organize the team: to see with all members of the sales team what are their expectations. I heard that some of them would like to leave the team: it may be a way to have new blood and new ideas in the team. Some of the employees would like to move to another product line: let them make a try of a few months, if their quota doesn’t improve then you may be able to send them back to their last job. Before making any move, you should send them to a training to motivate them. In that way they will see they are important to the company: you spend money on their training in order to have a better qualified team.
Second of all, you need to have a cohesive team. It exists some way to have one: you should organize a seminar that involves every one. You should choose a theme for the seminar like the Olympics Games: a way to represent the international strategy of the company. You could extend the seminar to other departments of the company and let them compete against each other: Like this the sales team could act like a united team.