Your Step 2 score really isn't that important with regards to securing a fellowship. Where you are receiving your residency training (especially if they have fellowships that you are interested in) and connections (a well-connected Chairperson and PD is invaluable) plays a major role.
basically step 1 is the major screening tool, but if you can do better on your step 2 you can kind of make up for the step 1 score that is less-than-outstanding. If, however, you do excellent on step 1 and are a US student you may consider just not taking step 2 till after the match just in case you do worse on step 2. They will look at BOTH scores if they are both on your application and take both into consideration.