Are you using compression when you back up the file? That could reduce the size of the file.
Depending on what you want to achieve, there are a couple of more alternatives:
- Only ship a full backup once a week, and differential backups the rest of the week.
- Do log shipping, and copy all your transaction-log backups to the remote site.
- Set up Transactional Replication for a continuous copying.
All these methods come with their pros and cons, and which is the best for you depends on your requirements.