If you can't override it from within your web space as described, then you need to ask your web host to increase the limit.
Remember also that the limit is per-file, so you can upload multiple files that add up to more than 2MB, as long as they are each less than 2MB.
Here is how you increase the 2MB limit. The reason I know this is that I installed "Gallery 2", which had the same problem.
Just add these 2 lines to the end of your .htaccess file:
php_value post_max_size 100M
php_value upload_max_filesize 10M
This works... I tested it with +3MB file and then I upload 8 +3MB photos with no problem.
Enjoy...