Do you know for sure that he's not getting enough breastmilk? It's virtually impossible to tell how much he's getting when nursing without weighing him pre- and post-feeding. If he's gaining well and wetting diapers frequently, then you don't need to worry! :)
As you may know, supplementing with formula will only exacerbate any supply issues you may have. The more you nurse, the more milk you'll make. Some simple things like oatmeal (whether by the bowl or in cookies!) can also have the effect of increasing your supply. Pumping can help (pump after he's nursed), but don't judge your production by how much you pump. Your little one is FAR more efficient than even the best pump. The extra stimulation can make your breasts think they should be producing more, though.
In general, I think if he's not showing signs of dehydration or hunger, then he's doing quite well. Looking at your schedule, I would add in a nursing session before each "meal," so he as the benefit of both the breastmilk and the taste of solids. Remember, all he needs up until one year is breastmilk. Solids are great and a fun way to explore new tastes and textures, but the bulk of his diet should still be breastmilk; so, nursing and then feeding solids is a good way to balance it. It can also be a less-stressful time to nurse, for you, since you know he'll be eating when he's finished.
The basic rule of thumb to ensure he's getting enough is, Feed on Demand! :) So keep nursing as much as he wants to, add in as much of the solid foods as he is interested in, and enjoy this exciting time. :) If you need further reassurance, you may want to consult with a lactation consultant. I can give you a number for one in the Sugar Land area if you're interested, a friend of a friend who's also a LC.
Hope this helps! :)