Just a tip about the QR that has made my life easier. If you can master the word problems, you will be in great shape since they are a favorite on the DAT. I picked up the Algebra I CliffsNotes (a small book) from the library and there is a section with all of the types of word problems I've found in practice tests i.e.: compound interest, rate problems, age, mixtures, etc. They are easier here than on the DAT, but if you know how to set them up, time will be on your side during the actual test.
I'm also using some of the Dummies guides for Trig and Algebra and they seem to cut right to the chase for what the DAT covers.
If you don't remember anything, then a class would help. At this point I feel comfortable brushing up even though I haven't taken math class for about 10 years.