Try adding the LinkSys NSLU2 device to the Asus router, it can server as MySQL and PHP server (has enough horsepower), will draw almost nil electricity (as compared to full grown server). Have a look at the pages at NSLU2 Linux pages. There is a complete description how to install opensource firmware (even full grown Debian Linux distro), install web server (lighttpd, thttpd, apache), php, mysql, postgresql, or anything alike...
I have this setup - Asus WL500g router and NSLU2 with harddisk - working very well...
Jiri