If your line allows for 30k/s upload I'm not sure why you set your upload limit to only 5k/s. Because of this, your download limit is artificially limited to 15k/s. I would set it the upload limit to 20-25k/s. Then set your download limit to 200k/s or so.
In order for aMule to utilize your upload bandwidth efficiently you need about 4-5 upload slots, so set "slot allocation" to your upload limit divided by 5 (e.g. if upload limit is 25k/s then use 5k/s for slot allocation).
I would set "Connection limits-> max connections" to something like 100-150.
Otherwise, I'd say your settings look fine.

Oh, the sources per file primarily depend on how popular a given file is. Try downloading a more popular file to see if you get more sources.