Don't do anything. Take time and plan, whether Pentax, Canon or whatever brand. The biggest camera show will be held in September, and you can expect many new cameras and lenses coming out. It is good to know and have choices, but at the very least, holding off means lower prices on the current models later. The K-7 is a great camera except for one problem, the high-ISO performance is not as good as the K-x or any of the latest models, even cheap ones. High-iso performance gives you higher shutter speed, more DOF, less motion blur, better image quality in dark places, or more details when you need it.
Also, realise that you are buying into a system, and you need to make sure there are suitable lenses. You will be increasingly stuck with the system as you invest in lenses and changing system is expensive. Find the lenses you will want to use over the next 2 years if not more and cost them out. Pentax cameras are great values, but their lenses are on average just as expensive, often more so when you talk about the better quality AF prime lenses. Unless you will be happy using old lenses (manual focusing and also more work setting correcct exposure), Pentax lenses are not cheap. You camera body will be out of date and not worth much after a few years, but lenses can continue to be used. For Pentax, the lenses will be more expensive than your cameras usually after a while.
You mentioned portraits. If it involves flash units, then know that Pentax flash is not known for the most accurate or the best featured. It has not updated its flash units for a while. The independent flash units are not much better though better value. Choices are limited, similar to the lens situation, as many independent makers do not make their flash units or lenses for Pentax cameras. You also mentioned action shooting. In less than ideal lighting, Pentax auto focusing leaves a lot to be desired compared to Canon or Nikon, in tracking and locking focus. Combined with the K-7's problem with high SO performance, you are a lot worse off in action shooting. If it involves shooting from a long way away, then you will have very poor choice in fast lenses, or lenses of 400mm or more. You can do it, but it will be very challenging shooting action from afar using slow zooms and insufficient shutter speed, noisy high ISO pictures, even when you can get the focus by manual pre-focusing and anticipating.
I think for macro and other applications where you can take time to focus, use old lenses, and have good control of lighting, Pentax is fine and with the right lens, great.
If you are not going to be really serious, then it is not so important, as you will not be buying a lot of lenses, or many very expensive lenses. And you will not need to upgrade to full frame cameras, which Pentax does not make. You do not need the fast auto focusing or specialised lenses, etc. If there is a good chance you will get increasingly serious, then you should consider more carefully how you invest.
Pentax has just had 2 quarters of profit, after a few years of losses. There is no guarantee it can continue to be profitable, as the pace of technology and camera updates seem to get quicker, or too quick for the weaker companies. There are changes going on that can make cameras quite different in a number of years. The mirrorless camera is one of them. Increasingly use of electronic technology to enhance images is another. Converging serious video with still cameras is also getting serious. Sensor technology is definitely something crtical to image quality. Pentax is not making mirrorless cameras like Samsung, Sony, Olympus and Panasonic. It does not have advanced video expertise lik Sony and Panasonic. It is not a high-tech electronic company like Sony, Panasonic or Samsung and it does not make sensors like them. So, consider carefully all aspects, before starting what may be a very expensive investment into one system.
Lastly, beware of those who post photos to show you how great a Pentax K-7 picture can be, shots of birds in flight and actions in poor light, etc. Believe me, it take a lot of skills and luck to get them. The reject rate for someone with less skills will ruin you hobby. The K-x is great value and very capable camera, but it has serious limitations compared to other cameras in its class in some types of shooting. Good luck. Take time and research.