Tumbleweed is a "for fun" badge; the implicit message is "we're sorry this question isn't working out for you; keep trying!"
See this for some great tips:
Getting attention for unanswered questions?
You can "bump" your thread by providing status and progress updates resulting from your own continued efforts to answer the question yourself. I usually do that unless I really hit a dead end with no further clues to follow. Some times I eventually bring about enough understanding to realise the answer, and thus post a resolution to my own problem.
If you have enough points, you can offer a bounty, promising to give some of your points to the person who correctly answers your question.
The key is persistence.
Nobody should want to find out the answer to your question more than you do -- so show us proof that you're actively working towards a solution! If you are serious and show evidence of your hard work others will be more willing to pitch in and help.
(and, in contrast, compare this with the "do all my work for me" types of lazy questions -- not saying your question is one of these, but only using it as an example of what does not work.)