I would like to second the suggestion of going through your family budget, and eliminating extraneous expenses. If you start now to practice the belt-tightening that could be necessary next year in order to pay out-of-pocket, then next year won’t be remotely as painful. You will already have cut your financial bad habits down to size. Go through your expenses with a fine-toothed comb. You may find that you needn’t alter your current retirement savings plan at all.
Each month, do your level best to slap 1/12 of the annual Cost of Attendance at the most likely UC right into some type of savings. If you feel like it, and there are any tax advantages for you, go ahead and set up a 529, but an plain old savings account will work too.