The easiest answer...if you want great looking prints with the most detail then buy Qimage.
Slightly less easy answer...are you using Windows 7? If so, then use the resizing function of your favorite software to crop and resize your image to 300 PPI. Then use the Windows Photo Viewer to print. WPV performs print sharpening, and will handle color space conversions. The results are great.
The hard answer...you are stepping into an area that is poorly understood by many. Getting the best resolution out of a printer is not straight-forward. In order to get the most detail on paper, you need to apply print sharpening to your image. Qimage does this, along with the correct resizing. WPV applies print sharpening, but doesn’t resize. There’s other software available that provides print sharpening functions, such as Nik Sharpener Pro, PhotoKit, LightRoom, and others. But applying print sharpening by hand is tricky. You can search Bing or Google for “output sharpening” and you’ll get lots of hits. There are lots of techniques out there.
Here’s an example of the same image printed first without and then with print sharpening...
The reason that images must be sharpened for printing is that printers don’t reproduce images the way a monitor does. With a monitor each pixel is completely separated from one another, and each has a thin black outline. When you print, one pixel is comprised of a matrix of dots. The dots overlap each other both within the matrix and on the boundaries between matrices. Because of this, images will lose detail and sharpness. So output sharpening is used to restore what was lost. It does so by tuning the image to the characteristics of the output device.
Output sharpening depends on the output device. If I were to print an image on an Epson I'd resize to 720 PPI and make the image look excessively sharpened. But if I were sending the image out to be printed, and I know the print shop uses a wet printer, then I would resize to the resolution of the wet printer and apply just a tiny amount of sharpening. This is a very device-dependent process.