I'm looking to purchase a Billion 7800 series but I thought I'd ask a couple of questions here first.

I'll say what I've got at the moment and then what I'm trying to do.
At present I have a sky fibre connection. The line is awesome. The router needs to go.
On our home network we have 8 computers that could be on at any one time, a couple of switches dotted around the house and most importantly two NAS(es?) I also have a Samsung galaxy s3 and my dad has an s2.
I'm currently living at home with my parents after having finished my degree and my dad and I are looking for something a little fancier when it comes to getting at our data when away from home. I'm currently studying towards a Cisco CCNA so I'm alright when it comes to networking but configuring vpns are new to me so I need a prod in the right direction

At present, I have ftp'd my nas which is not so bad but my dad is using some awful proprietary software that came with the nas to get his data.
I don't have a static ip from sky though I can get one if need be, however I have a domain name courtesy of dyndns to get around this problem.
What we would like to do is set up a vpn connection to our home network (using our dynamic name if possible) so we can basically browse the contents of our devices as though we were there but without actually being there. I also would like to use it for my internet connection because I know the connection in work is heavily monitored.
More than one user might log in at the same time too and we might use it for streaming too.
My research seems to suggest this idea is possible however I would like to be sure that I'm not talking gibberish and the 7800 can do it!

Thanks,
Mike