I want build a router to control my internet access (wlan via server).
Only a few websites (via white/blacklist) should be available at specific times.
Are there any good packages for routing/proxying web (http/s, ftp) and email (pop/imap/smtp) traffic?
If you need an HTTP proxy check out node-http-proxy. I don't know much about FTP and mail proxies though.
What you actually need is a good Firewall. Any decent firewall should be able to filter traffic by day-of-week and time-of-day. Even many of the better SOHO routers can do this. If your router can't do this, you should use a spare PC or server to act as a gateway, run Linux or BSD on that and configure a firewall accordingly. Most Linux versions have IPTABLES which is a simple but effective firewall which will do what you want.
To make things easy, set the PC up to be the DHCP server for the network and configure it so that, when other PC's get an IP address, the gateway IP is set to the same box (you may be able to get your normal router to do this instead otherwise turn off DHCP on the router).
Ideally, if using a gateway PC, set your routers to ONLY accept traffic from that gateway - better still, turn off NAT on the router and let the gateway do it too.
Here is a fairly comprehensive "how-to".
If all of that seems too much, you should consider upgrading your router to one that does all this for you. I personally use the Billion 7800N which would probably be suitable.