It's not really clear to me what you are angry about. Is it that your husband has gone out and spent the money? Or is it that you've just discovered that you aren't as rich as you thought you were, and you blame your husband for not informing you of this at his earliest opportunity?
As others have noted, you can try getting a bursary out of the school - but I would imagine that they would only give you short term assistance (ie, maybe a year), if your son hasn't gone through the process relating to bursary applications. Alternatively, you can start planning now for 13+ entries, and find another place for your son.
As also noted, state school allocation for next year has already happened, so you are probably going to struggle finding a place.