Mine came with a smaller dustbag too and it bothered me. You should definitely ask but don't get your hopes too high. In my situation, I returned to the store I purchased at and explained the situation and they pretty much told me "too bad." (I never purchased from them again). But I was determined and felt it was unjust for them to give customers a dustbag size that doesn't fit the bag so I called around several stores and went to others in person and got the same response. Finally, I encountered a very kind manager at the Wynn store in Las Vegas. She brought out several sizes of dustbags to show me and jsut let me have one. Great customer service!
For future reference, if you ever buy another speedy, it is best to make sure before purchasing. When I bought my azur I asked the SA whether she could give me a larger dustbag if I decided to purchase. She gave me this long lecture about thats how they come, that its meant to be stored folded and there is only one dustbag for each bag (which is a lie). I simply said thank you and walked away. Another SA in the same store exclaimed "Of course!" When I inquired and very happily accomodated me by giving me a larger dustbag with my purchase.