Well, your redundancy money is the first port of call followed by additional borrowings.
It is possible to enter into an agreement with a solicitor to defer payment of fees until the end of your case when there is a division of assets. However, if you are litigating over the children you could use up all of your capital without sorting out the finances which leaves your solicitor unpaid. The upshot is that a solicitor is unlikely to take that risk.
A litigation loan is also possible but, again, there has to be the prospect of being repaid which would usually be from a financial settlement.
Acting for yourself is another option as many people on this site have done.