Read this: http://support.apple.com/kb/HT5668. Also change your iCloud password so someone can't take over your account and access or delete your data.
You can access photo stream photos from the last 30 days by setting up iCloud on your computer and enabling photo stream (see https://www.apple.com/icloud/setup/). If you backed up your iPhone, you can recover your camera roll photos by restoring the backup to a replacement iPhone or iPod Touch.
This explains how to make copies of your iCloud data on icloud.com: http://support.apple.com/kb/ht4910.