Atropos7 has given you good and accurate advice on this. Irrespective of how you customize the PHP environment by modifying those settings in php.ini, you will not be able to use that amount of resources on a shared hosting plan. That level of resource usage will require a VPS (DreamHost PS) or Dedicated server with adequate resources reserved for your own private use.
What kind of help are you expecting with this problem? We can't help you run that on a shared server any more effectively than we can help you stuff an elephant into a mini-cooper. That said, if you really want to walk away, reply to me via PM with your WebID, or a domain name you are hosting at DreamHost, and I will arrange a pro-rated refund of your unused hosting time. Life is short, and there is no reason to hang around unhappy - I'll help you "walk away" without financial penalty if that is what you think will make you happy.
Well, it may be disappointing, but I don't think the BBB is a particularly useful resource for resolving web application programming issues (or for stuffing elephants into mini-coopers)!
--DreamHost Tech Support