I sympathize with your endeavour. I have a similar setup and it took some time to get there. The article noted is excellent.
Once you have a start on a config for the router you can post the config for us to have a look at.
/export hide-sensitive file=yourconfigsep31 just make sure you put in fake Ip addresses for the public facing WANIP (the one from your ISP)
The 260GS switches are not the friendliest beasts IMHO. Once setup correctly they work fine but getting them there is bound to drive you a little nuts.
Again I can certainly share the knowledge I have of my setup if that help you with your efforts. No sense in doing that though until the router is configured properly.
By the way just because the word GURU is next to my name it doesn't mean I know jack sheite.
I'd rather manage rats than software. Follow my advice at your own risk! (Sob & mkx forced me to write that!)