I've done something similar and from my experience the cleaner/sanitized/sterilized your process and equipment is the longer it will keep. Remember unfermented wort is a breading ground for just yucky stuff so keep it clean and you can hang on to it for many weeks.
Life is too short to drink crappy beer@
Kegged: Super Hoppy Red Ale, IPA
Bottle: Barleywine, Belgian Chocolate Red
Fermenting: India Brown, Pale Ale