Dreamhosta ticket attım , nasıl yükseltirim ya da siz yükseltir misiniz? dedim.
Cevap yazdılar , bunun mümkün olmadığından bahsediyorlar fakat bir yol olabileceğinden bahsedip ilgili bir link veriyorlar, ben içinden çıkamadım çözebilen olursa çok sevinicem.

Alıntı
Regretfully there is no way for us to change the 7MB PHP upload limit for
a single domain. It would have to be changed in our global PHP
installation, which we need to keep lean n' mean since it hosts over
350,000 domains. The upload limit is set at 7MB in an effort to keep our
/tmp folders from filling up, since a full /tmp folder means that pages
don't get served right on the server for EVERYONE on the server. Due to
this, we don't make custom changes for our users. The only way to
accomplish this is to recompile PHP (which IS overkill, but is seen as a
benchmark by our honchos that users KNOW what they are doing with the
changed setting):
http://wiki.dreamhost.com/index.php/Installing_PHP5

We do not provide any support for the above directions. Sorry!!

Thanks!
Glen