sg_87, I was in a somewhat similar place before I started grad school in that I had been out of undergrad for 5 years and did very little research when I was an undergrad (1 summer's worth of work that led to no pubs and the project wasn't terribly independent) when I applied for PhD programs. My advice, which will largely reflect what has already been said is #1 to figure out what you want to study. Start reading the primary literature and figure out what gets you excited so you can speak intelligently about it in your applications and interviews. Also as mentioned, there are funded M.S. programs, I'd even go so far as to say you shouldn't do a research masters that you have to pay for.
As far as making yourself as competitive as possible in the application process, I suggest two things that massively helped my application: studying really hard for the GREs (I ended up scoring well on the general & subject GREs and some I interviewed with commented on my scores reflecting that I was "really a scientist at heart", despite having limited experience in research) and getting some research experience. If you're willing to take a summer off, which sounds like it might be possible with your current job, check out field tech or other summer research positions on ecolog or evoldir. They won't pay well AT ALL, but they will give you experience and it's possible to find ones with free housing.
Good luck!
