For books on research methods search GIL-Find, the Library's online catalog. Here's a possible search strategy (limiting to books published since 2005):
Encyclopedia of Research Design is an online collection of entries written by scholars in the field of research design, the discipline of how to plan and conduct empirical research, including the use of both quantitative and qualitative methods.
Resources for downloading data for quantitative analysis, and for finding tests/measurement scales:
For policy analysis research: