As you have no male relatives to take a test that rules out yDNA tests.
The autosomal DNA (family finder) is most likely to be the best for you. It searches across all you ancestral branches so you could find missing one, second third cousins etc (provided you have some solid paper records). The test is only reliable for this back about 5 generations - but that is still a lot of potential new relatives. With this test you also get an ethnic makeup of your ancestry but a word of warning this is far from definitive and people often get disappointed with the alleged ethnic makeup that is suggested to them. This is probably more to do with the science being new and not robust enough rather than some deep dark secret lurking in you ancestry.
There is also the mtDNA test that just looks at you direct female line ie mother, grandmother etc and you will get your mtDNA haplogroup but then there is not a lot you can do with it.
You can usually get the autosomal and mtDNA tests together.
One other test is National Geographics DNA Geno 2.0 test, but I don't really know enough about it. Here is a link
http://shop.nationalgeographic.com/ngs/browse/productDetail.jsp?npd&npd&productId=2003825&gskIf you do go ahead and test what you get out of it will depend if you are lucky enough to have distant relatives who have also tested who you might make a match with. Although you may not get much information straight away you could be lucky in the future and make matches as more people test and the science becomes better
