Is there a way I can assign the "Admin Approval" to another group other than the administrators System Group ? I'd like to create a new Moderators group and assign the approval task to those members ? Thanks.

I currently use TwitterFeed to do mine. It's been around a few years and has some good options for filtering and when to fetch topics and so on. Also caters for Facebook and LinkedIN, though I can't say i've had much experience trying them. It uses your RSS feeds to get new topics. Personally I'd prefer a built-in option but it does the job.