Nothing wrong with the submitters youre using - I use the CS myself for the sites that accept autos - and I do my manual submits with their built in program - which is fine for most tgps - every pro submitter out there uses something like that.
The niches are probably the problem as they are very over saturated - every newbie submitter in the world is using those
Look for something a little smaller and tighter and Ill be your revenue goes up.
One other thing you didnt mention - are you using sponsor content or your own?