Just like you might be able to use .htaccess to override the PHP settings, you also might be able to use it to override the Apache settings. For example, placing the following line in .htaccess changes the limit on uploaded files to 10 MB:

LimitRequestBody 10240000 

Note that the limit is specified in bytes, not megabytes. Setting it to zero will make the setting unlimited. The highest number you can specify is 2147483647, or 2 GB.