If you are willing to learn, the K-7 isn't too advanced for a beginner. It does have an auto mode. If you are serious about learning you will soon be moving to Aperture Priority (AV) mode, Shutterspeed Priority (TV) and full manual (M).
However, if you never plan on taking your camera off of full auto then the KX would be a better choice. It will save you money because there are features on the K7 that you might never use. The KX is specifically targeted toward those just stepping up to DSLRs.
One thing you want to consider is that you be spending more money on lenses in the long run than on the body. Ultimately the lenses have a bigger impact on image quality than the body itself.
What you need to do is decide what features you really must have and what features you might be able to live without.
Here is a comparison of the KX and the K7 for technical specs.
Some of the big differances include, weathersealing, mirror-lockup, a bigger viewfinder and a faster possible shutterspeed in the K7.
Either camera would be an excellent camera to buy and will yield amazing results if you put the time in to learning the camera and honing your craft.