Hello and welcome!
Bunnies are usually introduced to greens around 7 weeks old. Since your bunny is around 8 weeks old now, it would be time for him to start eating greens: 1 cup per 3 lbs of bunny is usually the formula, and you want to follow this list to get a good idea of which veggies are best for daily salads (avoid things high in calcium and/or oxalic acid).
At this point, you should start phasing out the alfalfa pellets and start looking into Timothy hay pellets — Oxbow Adult Basics is a good option; basically you want something 15% or lower in protein, 20% or higher (the higher the better) in fiber. Slowly mix in the Timothy hay pellets with the alfalfa by greater quantities over about a week or so until you’re only feeding Timothy pellets.
These pellets will be constantly available to the bunny until they reach about 1 year old, at which point you should begin to decrease the pellet intake to about 1/2 cup daily. Read here for more diet details.
As for the hay: hay is the most important aspect of a rabbit’s diet, so if your bunny isn’t eating the hay you’re currently offering, try switching to another brand to see if they prefer it. They really need to be eating a lot of hay to keep a healthy digestive system running! 
Good luck!