I highly recommend the K1EL Winkeyer USB : http://www.k1el.com/
It is a kit that is only $79 and it is an easy build. It functions as both a standalone
keyer as well as a hardware keying interface that is supported by N1MM and other loggers
via USB. What this means is that N1MM will send data to the keyer and the keyer hardware is dedicated to controlling the timing for the keying the rig. It works just like the setup you currently have except it will give more reliable keying from the computer and it allows you to use the paddles as well as send from N1MM (i.e. allows you to use your paddles for "fills" while contesting with N1MM) . N1MM will control all of the functions like increasing and decreasing sending speed so nothing you do from N1MM actually changes.
If you are not contesting you can use it as a standalone keyer without connecting it to the computer. What is also handy is that you can connect two rigs to it and switch the paddles / keyer between the two rigs via a simple one letter command that you send from the paddles itself after pushing a button on the keyer.
It is an excellent keyer at very reasonable price. I have had mine for about a year and I love it.
I use N3FJPs loggers for contesting and this setup works well. I know that it is supported by N1MM as well.
Let me clarify...I know that I need some sort of external keyer. Does anyone know of a real easy keying circuit that can be build either on a bread board or with Manhattan style construction? I don't want to spend a fortune on a CMOS keyer that has memories and all the other bells and whistles. I can program N1MM for that. I just need a device to sit between my key and the rig.