Our district is similar in that it uses the CogAT and they are looking for a certain percentile (except they insist both verbal and quantitative need to be high, they don't care about non-verbal, strangely--a kid could score 150 on CogAT non-verbal and still not be eligible for gifted services...anyway I digress).
It sounds like the school does not use previous bad scores against the student, so it may be worth it to re-take it and just see what happens. If she doesn't get the scores would you consider outside testing, like doing the WISC?
DD went to the "self-contained" program and while I think it is an Ok option for some kids (kids who love writing, worksheets, and working in groups), I wasn't all that impressed. They had the kids all working on math at their own pace, without any real teacher instruction. The language arts teacher loved worksheets which DD hated and writing huge papers which DD also hated. When I enrolled her, I was hoping for a math program where she would actually be taught, not skip large amounts of material and be expected to work on her own. My younger child has the scores that he qualifies to go there as well, but I don't want him to. I think he would hate it. I guess my point is that you should ask about the programs and curriculum, and then determine whether you think the work/program is a good fit, esp. before investing any money in outside testing. Just because a school has a gifted program and a kid is gifted, doesn't mean the gifted program is a good fit.
