What sort of environment is this? If this is production, you needed those licenses yesterday. Evaluation Edition is not licensed for production.
The fact that you are going to change the server in October is irrelevant. You can get the proper licenses now and perform an edition upgrade. That is a fairly painless operation. Keep in mind that the license is not tied to the hardware; basically, it is a piece of paper. Of course, if you don't have internal funding to pay for the licenses now, you have a bit of a problem...
I should add that this is a forum for technical questions, and yours is more a commercial/legal one. I would recommend that you contact your local Microsoft office to see what agreements you can make.