[MENTION=24995]SV_Dude[/MENTION]
If I were in your shoes, I'd get rid of the HK asap, and put your money into the CZ now. I can't tell you how many times I've seen people spend literally thousands in ammo, sights, grips, etc. trying to get a pistol to shoot to their satisfaction. Eventually, they get rid of it anyway.
Look at the money you have already spent on the (way overpriced IMO) HK, plus the ammo and range time you have invested in it so far. When you finally do get your hands on the pistol thats truly meant for you, whether its a CZ or not, you will be glad you got rid of the HK sooner rather than later. I can promise you, a stock, out of the box CZ will shoot groups half the size you posted with no practice on your part.
Like I said earlier, once you get the fundamentals down, it shouldn't take that much effort to shoot a pistol well. I taught Military Police Swat officers to shoot for almost 8.5 years. I've seen people come in with zero shooting experience, (but are capable of being taught), shoot expert in a matter of minutes with the proper instruction. Then I've seen people come to the range with their privately owned whiz bang, new fangled, "Navy SEAL Operator" guns and embarrass themselves. In my experience, 90+% of the time its improper grip and trigger control. Once those 2 things are mastered, it comes down to what action/design fits you best. In my years of instruction, I have never found a person that didn't shoot a CZ well.
Here is a link with Todd Jarret instructing proper handgun grip. (around 1:02 in the video). This, single handedly, has helped a LOT of people shoot a handgun. It will feel awkward at first, but try it out and let me know what you think.
Todd Jarrett on pistol shooting. - YouTube
If you lived nearby, I'd love to spend a few minutes on the range with you. I have a pretty big selection of pistols to choose from. If you get a chance, goto a range that has rental guns and try out everything you can. Once you find what fits you, those groups will shrink dramatically! Good luck!