I have an old psychology book that specifically mentions this behavior as a sign of serious mental instability. I don't know how much stock I put in that book, but it does say that...
@OP: What's wrong with what you have now? Seriously: Identify the single biggest problem with your current setup, then perhaps we can help you tackle that problem with your stated budget. That really is a much better plan than just buying *something* hoping for *something* to be better.
Are you having noise problems? Are you getting nasty resonance sounds around a certain frequency range? Does your current setup ultimately result in recordings that lack clarity or low end or that sound muddy, "boxy" - or hollow, perhaps? Does your microphone not seem to "get along" with your voice in some other way that you just can't quite put your finger on? Maybe your mixes just aren't translating to other systems very well - These are just a few of many possible problems for which suggestions could be offered to you by other members with more experience that would actually address the issue. However, if you can't identify a specific problem - my honest suggestion would be to put that money in the bank until you can. In the meantime just keep working with what you have....somehow I doubt you'll take this suggestion, since it's a boring one - but I highly recommend you at least consider it.