Wait... I think it would need to be somewhere just beyond L2...
In an unstable orbit... If the orbit could somehow be maintained, then in theory at least, all (or most) of the force used to maintain the unstable orbital position would be imparted into the Earth's orbit...
It would take a long time. And a lot of energy.
But then like I said,
I'm just making all this up so you better talk to some real experts.
Scott Evil