Okay, here is what you need to do.
1. Open the php.ini file provided by bluehost and change the post_max_size and the upload_max_filesize to the value you want. So, to increase the maximum to 50 meg, they would need to be like this:
upload_max_filesize = 50M
post_max_size = 50M
Don't change anything else and save the changes.
2. Leave this in your public_html root and also copy it to the following locations...this is assuming Moodle is installed in a directory called moodle:
3. Also, copy this to the root of your moodledata directory.
Now, log into Moodle and go to Site Administration/Security/Site policies and change the "Maximum uploaded file size" to either "Server Limit" or your new max limit and save.
That should do it.
Just write this down somewhere so when/if you upgrade you can add php.ini back to the appropriate directories.