you could probably dissolve the DME in a separate pot of boiling water and add it to your cooling wort. Will be faster than reheating your whole wort. Probably some math to be done here as you'll be adding some liquid as well... but it could be very concentrated I imagine. Just guessing, I've never really done the DME addition. If it's off... oh well, adjust for the next batch. The difference in final product will likely not be huge. Since you're just one batch in, you'll likely still be happy withe the beer you make and you'll fine tune as you move forward.
