Hi Angie! Welcome to the group. Congrats on your son reading 300 words, that is a huge accomplishement! Keep feeding him words and introduce some gentle pattern phonics and he'll be decoding in no time.
Have you downloaded the 2 week trial yet for Little Reader? There are some great ebooks available too from the BrillBaby link above. And make sure to check out
http://forum.brillkids.com/parents-with-special-needs-children/ Keep us updated on how he's doing!