Annie,
You can actually put those data files just about anywhere and set the permissions to 755 or 777 (whichever works for you), if your hosting provider allows .htacces files.
For instance you could put the Moodle web files in/public_html/moodle. Then you could put the data files in /public_html/moodledata.
Since you don't have access to the the httpd config file you will need to set up a .htaccess file that controls access to the files in the data folders.
Here is the content of one .htaccess that I am using in one of my play around Moodle's data folder.
deny from all
AllowOverride None
AddType x-mapp-php5 .php
The first line prevents anyone from browsing the data folder but scrips will still work. The second stops any over rides. The third line is telling it to use php 5 because my provider has multiple versions of php available.
And in the corresponding web folder I have an .htaccess telling it which php to use.
AddType x-mapp-php5 .php
Further reading at http://www.freewebmasterhelp.com/tutorials/htaccess/1 is one place that will tell you more about .htaccess files.
HTH,
AL