The open software is usually pretty "light" when it comes to features and power. As such, it will normally run OK on any soundcard including the realtecs and others.
My first excursion into recording was with an early Cakewalk program and a PCI card. It worked ok but with the PCI card and it's software, recording was not the easiest thing to do. Then an OS upgrade made the PCI card non-functional so I got out of recording for a few years.
When I decided to get back in to recording after having been out for a few years, I determined to get my rig "right" this time. I was going to do what was necessary to get a reliable and easy to use DAW. To me, that included decent recording software (Music Creator) and the purchase of a computer that could handle the software easily and most importantly, a dedicated external interface/sound card for the laptop.
It took me a few days to get it configured correctly. But a few kind and dedicated users here in this forum, worked with me to get the settings on the soundcard correct, and once I got it working, I have not looked back since.
With a proper interface, all the data can flow smoothly to where it needs to be and in a timely manner. This makes for a pleasant recording experience.
I consider the Interface/sound card to be the HEART of your studio. So when you choose one, be sure it has Audio and Midi built into one unit, be sure the number of inputs are sufficient for you.... ( MC6 will only support 2 live inputs at a time so a 2 audio channel interface is sufficient) , be sure it is USB and uses (native) ASIO drivers and not some sort of driver emulator. M-Audio, Focusrite, Presonus, are all good candidates. You will probably spend between $100 to $200 to get a decent interface. Don't be afraid to spend a bit over that if the interface has features that you like. If there is one area in the studio you need to spend money on, it is the interface.
How much further you wish to go with this hobby will depend on your goals and desires. It is possible to spend a lot of money to end up with a really first class home studio, but ultimately that is your call. For now, get a good interface and see the difference it will make in the process.