Waiting is a good plan with regards to money, assuming that he is currently still paying the household bills. If he is not then you will need to file and then ask for temp orders to obligate him to pay.
Courts generally look at the past 3 years of tax filing/W2 forms to determine income potential. This is because sometime people will quit their job in an effort to avoid paying CS or SS, so the court looks at their income history rather than just their current income. However, it would be better for you if he already has a better paying job.
The other thing to consider is visitation. If he lives out of state then he may be granted longer visitation periods during school breaks. If you are clever and lucky then you may be able to get language that he is responsible for all transportation since he is the one that moved, but don't count on that. If you file and are able to get a judgement before he moves then he will likely get more standard visitation and would have to go back to court to get it changed after he moves. I do not know how long the entire D process takes in your state, so he may have already moved before you get a D settlement so this issue may not change based upon when you file.
You also need to consider that if you file now, he may decide not to take the other job out of state.
Consider all of your options, but it does look like it is in your best interest to wait for him to take the new job and move.
In the mean time, get your ducks in a row. Find all of the pertinent financial information, including tax records, credit card statements, loan statements, mortgage or rent agreement, 401K and/or pension statements, back statements, etc. Also research the laws in your state AND the state where he will be moving (he may try to counter sue from the new state). Interview some L so when you are ready to retain one then you can do it immediately. Also start to squirrel away some cash -- when you go to the grocery store get $10-20 money back if you pay with debit card, or buy some gift cards from grocery store or Walmart, etc. Stash it somewhere safe so you can use it in the event that he stops paying bills.