The 18-55 is a very capable lens, I think that the issues I'm seeing, as Geof pointed out could well just be down to it being a low res Facebook pic.
Possibly try using photobucket or the likes so it doesn't get massacred.
As an aside, I do recommend the 50mm 1.8, not because there's anything wrong with the 18-55, but because the 50 is a cracking little lens for the price.