Patchy and weedy lawn
 

I had my lawn done last June and have the following problems:
Uneven growth
Patchy
Bare and weedy in places

I've attached some picture links - can anyone give me some advice on how to treat these problems? Thanks in advance.

http://i125.photobucket.com/albums/p...n/P1010531.jpg
http://i125.photobucket.com/albums/p...n/P1010530.jpg
http://i125.photobucket.com/albums/p...n/P1010529.jpg
http://i125.photobucket.com/albums/p...n/P1010528.jpg