Hi friends, got a question about equipment

Hi friends,
I own the 8.5 sonar version with an APRO-500 and the e-mu 1818 sound card.
Now everything works great for me, but recently I decided I want to start recording vocals and bass.
so here is the problem, I have no idea what should I buy with the lowest sum of money for getting high quality recording.
I guess all I need is an analog mixer with a phantom and a dynamic mic.
can you help me to find the specific models of the items I should buy?
thanks in advanced,
Ami.

That's a really open ended question.
I am quite happy with my MXL 990/991 mic package, but others don't like them. Mic choices can be highly subjective.
Do not get a mixer or mic that uses a USB connection. These will introduce a second interface, and will defeat the superb performance of your E-MU card.
At a minimal investment, the Behringer Xenyx802 will make a decent front end for you.
Check the specs, and get the best you can afford.

ok, well, I thought about the sm57 mic, I heard it's pretty good with the Xenyx1002 mixer that has additional 2 inputs.
Do I need preamps or something in addition to what I think to buy (in comparison to my needs) or is it all?
Other suggestions Would be welcome.
thanks again,
Ami.

I spent an hour trying to find specifications  of EMU 1818, no success. Then I tried to find information about APRO 500, which is a vitamin pill. A-500PRO would be a keyboard, which I suppose is what you are using :o)
But still..

Does 1818 not have phantom power? Anyway, Shure sm57 is a dynamic mic, which can't use phantom, only condenser mics use phantom.

I don't understand why you would need a mixer? It may be handy sometimes, but if you're on a budget, why spent money on that? You're not recording vocals and bass at the same time, are you? Also, you're not telling if you're micing an amp or recording directly into SONAR. 
Are you working alone or recordintg a band?
 
Depending on the 1818s inputs, it may be you need a pre-amp for the bass.
I don't know what's your definition of "high quality", but as the only mic sm57 is usable, but maybe not very high quality for vocals.