You should have access to php.ini file and should be able to restart your server, otherwise you need to contact your hosting provider to do that for you.
Here is a nice little script I use for problems like your having.
Staggered import of large and very large MySQL Dumps (like phpMyAdmin dumps) even through the web servers with hard runtime limit and those in safe mode. The script imports only a small part of the huge dump and restarts itself. The next session starts where the last was stopped.