Rookie looking amp/receiver advice

I am attempting to put a decent "quality" system together for my son. I have about $500 left to spend. Currently have him a set of Monitor Audio BR2's for his mains. This will be his personal stereo for his dorm/room only for the next 4 years as he is headed to college in September.
I currently have BR2's hooked up to my old Yamaha RX-V495 receiver and an old Sony CD player. My question is would I see a big improvement in sound quality with a decent amp/receiver? Or is my Yamaha adequate?
My overall question is what direction would you take at this point with the money I have left to spend? Thanks in advance for your help!

Does he listen to or need surround sound?
If not what about an inexpensive but durable integrated amp.
Just another way to look at things.
I would put the money into a headphone amp and a pair of headphones. They just may come in handy.
No need for surround at this point. This will stay in his dorm and room in his apartment. When he moves to an apt or house next year I will get him a decent 5 channel receiver and a big ole set of cerwin vegas or something similar. That way if they get damaged its not a huge deal.

He has a set of bose headphones he uses with his laptop/iphone. Those should be ok for him for now.

What amp would you look at to run those speakers? From what I have found seems as if an older used Rotel amp/tuner may be a good option? I will add a powered sub at some point.

Would it be wise to look at a good receiver?

With the new models coming out, a older Rega Brio might be a good solution. Price should be in the range. No remote, but also pretty well bulletproof and 50Wpc is plenty for a dorm. A nice stepping stone to better hi-fi after college too.
His generation is tied to PC's for music. Get him something like an idecco with a USB input to stream music. Radio means nothing, what kids even use cd's?

Spend an extra $75 on a back up hard drive for his pc as well. That could save his life, grades, career and more...
Went another direction. Purchased him a set of b&w 685's. He is set for many years of quality listening. Went and listened and he loved them. Will sell the MA's, and will start the search for what will run the 685's. I most likely will look at a good used NAD PE, Rotel Receiver, Maybe even one of the newer HK 3490. Good cables/wires and he should be set.