Need new router or just hub/switch?

I currently am using a home network router with 4 LAN ports. They are all full. I would like to add at least 1 more device on the network with the possibility of another in the future.

Currently on my network I have the following utilizing the four lan ports:
1. PC #1
2. PC #2
3. Xbox Live on kids basement tv
4. Internet video device (Netflix, Youtube ect) on living room tv

I would like to add another internet video device on a bedroom tv.
I thought I would jsut get a new router with 8 Lan ports but saw most were quite expensive.

Can I use an inexpensive hub along with my existing router?

The current #4 internet video device would more then likely not be in use at the same time as the new bedroom iv device.

Also I am considering the possibility of a third pc/laptop connection in the future.

Thanks