Will I be able to get my passport the same day I do biometrics at the DC embassy?Otherwise, how long does it take to get my passport back and how will it be shipped. Also, will they hold on to my old passport (still 3 months to expiration).

If your passport will be shipped back to you, then your old passport will be held by the embassy and returned with the new. For shipping, you must provide a prepaid priory mail envelope. Ensure that the mail is certified (embassy officials insist on this). Certified mail simply means that you'd pay an extra 3usd or so at the post office and get a green sticker that you affix to the envelope. It is meant to provide an extra layer of security and provides you a mailing receipt and electronic verification of delivery or delivery attempt.

Nope. The new passport will take about 3 months to be ready (based on report from those who applied in the last few weeks). You will be given your old passport if you plan to come back to pickup the new one. But if you want it shipped to you, then you'll be asked to drop the old one