my only two cents, i would wait until next year. at this point, i am assuming you are around 25 or so and still young if you apply at the ripe old age of 26 (my current age)
I think a 640 is strong for Georgetown, Vandy, Indiana
I had to re-take the GMAT as well (originally I had a 650), and it will be extremely stressful/difficult to knock out visits, essay planning and editing, resume editing, applications, recommendations in short order - since most Rd 2 deadlines are in the 1st week of January.
If I were you, I'd continue gaining great experience, sign up for an Accounting + Statistics Class at a local program, ace them to settle worries about quant, take your time and take the GMAT in April-June timeframe, then with a new score you can re-evaluate and really refine your Haas essays as well as your other top choices.
I found it difficult to balance work, apps, essays, and GMAT re-take at once; i only made it for Round 1 this year because i started very early (june timeframe)
Either way it is a personal choice, just a few issues to think about, if you are generally happy in your job now just get 1 more year, expand on some experiences - volunteering and the classes I mentioned, then you can strategically pace yourself, have time to prep your recommenders so they have more time to write a well-thought out answers to recommender questions, and of course to study and re-take the GMAT so you are not burnt out
as far as another school, i'd look into MIT, I am interviewing there in a few weeks and can provide you some better intel, i visited and loved it, one of my good friends is there and focusing on sustainable development. they are a great, fun, down-to-earth community up there. he has some great opportunities - MIT does externships in January - he is working with Department of Energy and then of course the summer internship - he got one at GE. So great opportunities in those areas you mentioned + great finance / strategy programs as well, what i like the most is there approach to letting you explore different areas wheras most school prefer you to have a very pinpoint career path
good luck with whaetver you decide, you have obviously worked hard to help others and I hope you get what you want out of this process
take care and sorry for this post alex, i know you are the true expert