Work around Error 413 request entity too large
Two ways to get it work, manual chunk upload or by tools.
You can use Real Ajax Uploader tool. It can used with html5 the upload of the files is done by chunks, with small request to the server for perfomance and robustness.
Or manually split the files to many chunks then upload them one by one. you can use 7-zip to split file and combine files. here is an tutorial.
For client split you also refer to File uploads; How to utilize "chunking"?
For sever chunk combine you can refer to Handling plupload's chunked uploads on the server-side and http://www.phpclasses.org/package/8858-PHP-Create-and-merge-Zip-archives-split-in-parts.html
hope it helps.
You can override default values of upload_max_filesize and post_max_size. Both of these two ini settings have change mode as PHP_INI_PERDIR which means you can either use one of the following
php.ini, .htaccess, httpd.conf, .user.ini
Since you're using shared hosting so best suitable option is .htaccess or .user.ini
You can refer this to set values using htaccessSet php Ini settings using htaccess