It is very important to understand that the gender of a noun is the most important element to learn when learning the German language. Without knowing the gender of a noun, it is impossible to properly form a sentence correctly. If the course fails to include the article when teaching nouns, it should be avoided.
For example, if the course only teaches you that "Haus" is the word for "house", it should be avoided. The course must teach you that "house" is "das Haus/die Häuser".
Deutsch Welle (DW) is a good place to get supplemental learning material. In addition to their website, they have some audio podcasts on iTunes. I like the slow news podcast, where the current events are read slower than they are in normal new broadcasts.
The only problem with the DW is that they are designed for multinational students living in Germany. The vocabulary lists are not going to have English translations in many cases.
If you are looking for a really good online course, you might try Duolingo. It is free, fun and slightly addictive.
Two absolutely essential resources are the dict.cc and leo.de websites. Both sites are off-shoots of the Mr. Honey German dictionaries available at Gutenberg.org by Winfried Honig. Dict.cc allows you to download their entire database for your personal use. I downloaded it. It is a CSV of over 1 million rows.
Lastly, be sure to look at youtube.de as a source of German material. There are a large number of German language audio books available including many kids books. I constantly listen to German audio books. There is nothing better for students who are not around German language speakers on a regular basis than listening to German language books. I recommend the speakers David Nathan, Dietmar Wunder, and the great Dirk Bach.