I attended a poorly ranked school for my undergraduate education. Will this affect my chances for a PhD in economics?
As the commenters have pointed out, a lot will depend on your ability to get good letters of recommendation. However, there is an important issue to note: a good letter of recommendation does not mean the same thing as "a letter from someone famous." You can get a letter of recommendation from a big name that is completely useless, if it doesn't provide any real information of value about the candidate. 

Instead, what you want are people who can testify that you are a good student, and show evidence that you can become a good researcher. Since you have excellent records, and are working with a research group before applying to graduate school, I think you have the right groundwork for getting good letters. To make sure that you do so, you'll want to meet with the people who will be writing the letters, make sure that they are willing and enthusiastic about writing the letters (hint: if they are at all hesitant, do not get a letter from them!), and then provide them with the necessary material they'll need (CV's, samples of writing and research work, citations and awards, etc.) to write the letter. 

Ultimately, the only way attending an unranked school will affect your chances of getting in as a graduate student is if the admissions committee at the school you're applying to shows such a bias. If you're concerned about such a possibility, and have the resources (time, money, motivation) to do so, setting up a meeting with the person in charge of graduate admissions at the department you're interested in probably can't hurt.