ちゃんとした文にするならこんな感じじゃないのかな？
site details の前に the 要らない？

I'm sorry to take precious gaming time away from you.
But I've just started a new clan called the 360 union,
so if you're interested, reply back for (the) site details.
Also if you're already in a clan, I would like to put
your clan site link on the union site and you could, too.