nas - amp advice for a total newbie.....

Hi I am stuck and am need some advice from your good selves please.

I have a macbook and an ipad which me and my partner share. Am looking for a NAS ( been told synology are good ) to store all our combined music on . 

I would then like an amp ( to connect to my Mission x 3 speakers ) , which i can connect to the nas and play the music off. one with interent radio would be good too. 

All the music is on itunes so would need an itunes server i presume and would operate form the macbook/ipad. 

Would somehting like an Onkyo amp work ( 8050 ) or am I better getting something else. 

Am really open to suggestions as my knowledge level is terribly low . Budget wise say up to £500 for the amp. For the Nas probbaly around £250 ( for 1tb storage ) 

Cheers M