It's a little late to answer your question. I'm not officially diagnosed, however I am going in for my result of my assessment next week (and the lady who did my assessment said it was very much likely I do have Aspergers).

Anyway, to answer your question, I often get manic episodes and my symptoms are similar to bipolar symptoms as are the depressive episode symptoms I get. My emotions in general are extremely up and down however, I don't think it's extreme enough or distinctive enough for bipolar (in my personal experience). My therapist doesn't think I'm bipolar as the last manic episode I had was about 4 months ago and I wasn't seeing her then and my Asperger symptoms make it difficult for me to explain things properly so she doesn't think it was a manic episode. Same with depressive episodes I've experienced in the last few months (apparently I'm not depressed - done by a formal assessment -____-).

Are the hypomanic/depressive times very distinctive? And like Lexi232 said, try seeing another psych-doctor to get a second opinion. It might be useful since I do believe that bipolar can be co-morbid with Aspergers and it may be that you have bipolar too (I'm not a doctor though so I'll shush now).