Hi Bater. I have listened to your stuff and the quality of the recording is really not that bad for a home recording. Maybe recorded a bit harsh with some distortion, vocals ar a bit dry and flat sounding. That can be cured by adjusting record levels and post record adding a touch of reverb, air and warmth with some plugins. My advice is to keep it simple. I would look at using a good simple audio interface with phantom power and a good studio valve condenser mic to record a good clean natural sound. You need a mic that does not add anything or take anything away from the record source. Use post record plugins to adjust and edit the sound to your liking. Many preamps add tones, colour etc that create a false unnatural sound. There are some very good chinese studio valve amps about available at around $100 and a good interface is relatively cheap. I have seen many suitable for your use on ebay. I am afraid I have never used Sonar or cakewalk I use Cubase but I am sure the principals are the same. I have just bought a few mics etc myself including a Neumann but also have a SE electronics condenser that does a great job it cost well under $100 on ebay.
There are also a lot of valve plugins etc that will give the same results as preamp hardware.

JIM