Increasing PHP memory and exec time on VPS


I’ve been having problems with BackupBuddy’s Export Site function. (BackupBuddy is a popular Wordpress plugin.) BuB tech support has asked (among other things) the following:

[quote]6 : Could you please find out what the current PHP Max Execution time on your servers is, and ask your host to maybe increase it to something like 200 or even 1000 (we try to go even higher like 7200) please? That may hopefully produce different results.

7 : Could you please share your existing PHP allowed memory (with which your Export doesn’t work), and ask your host to increase it please to something larger (the largest possible that your host will allow), and then try an Export?[/quote]

It appears that my current allowed memory is 90M and my max execution time is 30 (ouch).

I am assuming (perhaps incorrectly) that Dreamhost support will tell me that I need to make the changes myself. I have a VPS account and very limited PHP (and general under the hood) skills. Can anyone tell me how to do this, or point me to a tutorial? Or am I playing with fire if I attempt to do so?