To access a user's Dropbox account via the API, your app will need to be authorized by the user. The Dropbox API currently requires that this authorization be done via the OAuth flow. You only need to perform this step once per user though, as you can store and reuse the access token for each user.
It sounds like you intend to use only one account though (your own), so you can just process this flow once manually yourself, and save and reuse the access token programmatically.