Networking gigabit managed ethernet switch

I have a small music company, with 7 computers, 6 of them mac and one is running XP. I currently have a D-Link 4 port wireless router, but I have outgrown the number of ports. I am new to the high end networking stuff, and a freind said I am not using my network very efficiently. I have to reset the router a lot because I am boggin it down. What gigabit ethernet switch should I buy that is managed, and has at least 8-10 ports on it. The wireless is ok for now, but I want the data transfer between computers and the servert to be as fast as possible, without bogging down. I was hoping to spend under $500. Does anyone know the right choice to purchase? Thanks.