Could someone tell me how to change the names of the charities Good sims can donate to? E.G. 'Toilets for Tots' to 'Toys for Tots'. I can't seem to find the right file. Someone please point me in the right direction.

As is most of the text in game you should be able to find them in the STBLs in the DeltaBuild0 package in your Sims 3 installation folder.

Ah, thank you. Can you tell me if there's a good program to edit stblswith? I've tried this with a custom name replacement mod and all was well until I installed the package and then a new sim moved in and I got a message like instead of the usual 'visit household of family name' it said this below
Gameplay/Excel/EP05_World/Household: Jenner household

Or if anybody knows how to stop that filepath stuff from occurring I'd love to know!

Also must I edit the whole English Strings file as part of a package to simple change the name of the charities? If not how do I separate them out?

Here's a potentially helpful thread: http://modthesims.info/t/452081 which links to another potentially helpful thread: http://modthesims.info/t/showthread.php?t=360093

I'm not sure if the tool linked there still works though. If it does, all's well, but if it doesn't you can easily perform what the tool does using s3pe. Basically create a new package and in it create a new STBL resource. (Resource > Add. Choose STBL for Type and type 0 for Group. Read the Instances section in the second link above for what you can use as your Instance)

Then search through the default game strings in the DeltaBuild0 STBL for all the strings that you want to change and jot down their hash numbers. Then for each one just add a new entry with the same hash number in the STBL in your new package and type in the text that you want to show up in game to replace the default text. Save your package and so long as you managed to give your STBL resource an Instance as specified that should work.

Thanks!