Wa `alaykum As-Salamu wa Rahmatullahi wa Barakatuh.

 

‘Ilaa’ is for four months. If a husband swears he will not sleep with his wife for the period of four months or more, she should raise her claim to the judge who will give him the choice of either divorcing her or return back with an expiation of his oath.

 

In your case, you should observe a full `iddah for three consecutive menstruation period.  By the start of the third menstruation period you can get married to another person.

 

Almighty Allah knows best.