I'm currently making an ID3 tag batch editing app that will solve this issue, and it should be done within the month (I have to pollish it up a bit).
Basically what's happening is that the set of songs may have the same Album Name and Artist Name associated with them, but they might have a different Album Artist. The Album Artist tag commonly occurs when a song is featuring more than one artist. If the songs have the same Album Name, but a different Album Artist, the player thinks they are just two separate albums that happen to have the same name. So basically what you have to do is make all the songs on that album have the same Album Artist, and then the albums will no longer be split.
As for the album art problem, the album art is usually stored in each music file. However it is also possible for it to be stored as the file-name of the picture in the same directory. If it fails to find the picture, or it's named something else, the album art will not show up.
Now for a quick fix, the only other app that allows you to edit the Album Artist tag appears to be "iTag", but you will have to edit each song one-by-one.
If you are having any other gripes with your music player, I would love to hear about them, so I can consider other fixes that I implement.