Another option is if you know someone willing, is pull 4K from their account into yours. Marriott T&Cs state that spouses can combine points for awards, but Marriott actually will let any two persons to combine their points.

If you do have someone with an extra 4K points they are willing to share with you, just call MR, tell them what you want to do and they should be able to walk you through the process. (It involves receiving a form, filling out your part of it. Getting your friend to fill out their part of if. And then returning it via scanning/email or faxing to Marriott Rewards.)