Well, this is question best answered by what you want the best sound out of. Obviously, you want your voice to one thing best exemplified through your tracks considering you put this under singing. Being an amatuer engineer, Ive found that you can use relatively cheap software to get a decent sound. It sounds like you have put all you money into the wrong things, even though having good sofware is very important.
For vocals, the quality of your microphones are essential. Note that I did not say expensive. What you need is a condenser mic (powered microphone) not a dynamic mic ("karaoke mics", "stage mics"). Condensor Mics are best for Vocals and Acoustic Instruments. Dynamic mics are great for recording amps or playing karaoke at the house or being on stage (because they are run through a powered mixer), not good for recording vocal.
You may already have a condenser mic. Great!!! Thats one more thing that you dont have to buy. Here are some tips to dry up your sound. If you are already using a condenser mic and are getting crappy sound, chances are you are not recording in the right type of atmosphere. You need to shut off any source of noise that might be in your room (fans, tvs, radios, anything that makes a subtle noise that you think might give off any lower or higher pitch sounds. Your goal is to ISOLATE your sound. Go look at pictures of sound rooms on Google. They are going to have funny looking materials on the walls and a type of cusions in the corners. The purpose of these materials is to absorb sound (cutting out echoes and reverberation to best capture your voice) Try putting pillows in the corners of your room and blankets or eggcrate on the walls. This will clean up your sound BIG TIME.
Mic position is also very important and varies from person to person. I would also highly suggest for vocalist OR anyone who using mic at all to own a mixer. If you are using a computer, make sure it has either usb or firewire capabilities. Most people dont have firewire. This helps a ton in CONTROLLING your sound.
One last thing, DONT get Frustrated. I know it is easy to. Perservererance is going to serve you HUGE rewards. Experiment with what you have. Tight budgets usually pay off in creativity.
Seth Bialo