Way to improve in setting my network at home.

Hello,

I trying to setup a home network. I have the following equipment:

1. Netgear N300 Wireless ADSL Router
1. Apple Airport Express
1. QNAP TS-259

I have connected the Netgear N300 to BT phone-line to get internet connection. I then connected the QNAP and Airport Express to the router network ports. The Airport Express is hone connect to my Bose system.

I play music from the MAC Pro wireless to the router which sends the signal to the Airport Express to the Bose system. My girlfriend uses her laptop to access the internet.

Here are my questions:
1. The laptop that is accessing the internet is slow, is this due to me playing music via the other laptop that causes the poor performance? If so, how do I resolve this?

2. I have sometime find that the music played through my MAC laptop sometimes lags in delivering the music to the Bose system, is this the same problem as the first? How do I resole this?

3. I also like to connect other devices like the printer to the router as well. Should I look into getting a LAN switches? Will this improve the performance?

4. With the NAS connected to the router, is this safe enough to protect the data on the NAS box?

5. What is the best software on the market I can use to access my has remotely when I am in another country?

I want to know what is the best and efficient in setting up my network so I get the best performance and it is secure.

Thanks for your help in advance,
Dennis