Any way to Content serve via Twonky?

[enonod]

I have a Zyxel LAN NAS with a Twonky DNLA Media Server which serves films and music to TV and Android Tablet. The centre of the LAN is the BT Homehub. The purpose was both safety of content and not having to leave the PC on to do the serving.
The NAS houses my Calibre Library and I use Calibre Companion on the Android Tablet.
This means that I have to leave the PC on to run Calibre to serve the books from the always on NAS.

Is there a way around this problem, so that I can obtain the books from the NAS *other* than pre-copying them or using the Tablet LAN file browser to copy them (basically because the library folder structure would make it tedious)?

Or can the NAS be accessed via the Internet using the Calibre Companion?
[EDIT] There is a built in web server and ftp server but I do not know enough about it.