Praise be to Allaah.
Yes, you are entitled to maintenance during the ‘iddah, because the separation happened because of the husband, since he left Islam. Imaam al-Shaafa'i (may Allaah have mercy on him) said in Kitaab al-Umm (vol. 6), “If he – i.e., the husband – becomes an apostate (leaves Islam), he should still spend on her (maintenance) – i.e., the wife – during her ‘iddah, because she is not finally divorced until the ‘iddah is over.”
Sheikh Muhammed Salih Al-Munajjid