Job Offer Timing Not Working Out - Re-Accept Declined Position?

In a bit of a predicament and wanted to get some advice from the community as I've found everyone's input here beneficial in the past (using a throwaway account for anonymity).

Long story short I applied for a dream job months ago, made it through the process and finally received an offer, BUT also applied to business school (since the job was by no means guaranteed), and received interviews at two of my dream schools (top 5 programs). Problem is the firm couldn't hold their offer open another few weeks for decisions to be released so I declined due to family reasons (didn't want to accept only to renege since it's a considerable move; also extended the decision period as long as I reasonably could), but am now regretting that decision - both turning it down and not being totally forthright in wanting to take it but declining due to timing.

Their opening is not one that's easy to fill quickly, so I doubt it's been filled, but my issue now is how, if at all, to tell them I've reconsidered and would like to accept the position, but can't give a formal yes/no for a few more weeks. Obviously no one likes being second choice or being strung along, but one of these MBA programs doesn't permit deferrals, and just getting an interview was a crapshoot. Best case scenario is being able to accept the offer officially or getting into an MBA program, while worst case is having neither and being back at square one. Yes, I didn't play my hand as strategically as I should have, hence my regret, but my gut says to reach out, tell them where I currently stand and what I want, and get them to give me more time. Should I do that now? Wait until MBA decisions are released? Or not do it at all and reap what I've sown? I also want to maintain a good relationship over the long term.

What would you do? Appreciate everyone's advice.