My experience in publishing which dates back some forty years is that today even an iPhone will do the job *in the right hands*, but one must master the craft to accomplish it. With the exception of low-end p&s models and highly compressed jpeg images, nearly any salary and many premium p&s cameras properly set up and used well will produce images quite useable for both print and web.
I've had hundreds of photos used on the web and print with many covers and double page spreads even from my old 6MP jpegs and my higher end p&s camera. No problems for the editors but all from well crafted and properly prepared and edited files. Editing and crafting are the key.
Working backwards form the end result is the way you form your roadmap. If you are going for a cover, your image has got to be stunning and the best technical quality. However, if the work is to support and article with the words as the major thrust and images are a secondary facet, stunning images and quality are not quite as important other than to meet the mechanical and editorial requirements of the publication.
For both web and 95 percent of print media, high MP cameras as overkill. I'd say go with what you have and simply improve your skills rather than trying to improve the equipment unless there's an issue with the mecanics of the camera. In that case, just get another k5 if there are problems with the older camera, but check the other camera because it may be just the settings that may need tweaking to get its best performance.