Try your hand at simpler canework to build your skills before you tackle a complex logo. Use a good brand of fresh clay. Premo, Pardo and Kato are the three brands most people use. There may not be too much selection at your local craft store, so be prepared to order what you need online. There are several great resource sites online, so I encourage you to visit them. Pay particular attention to caning technique, reduction, baking and finishing.
While a pasta machine isn't a must have, it cuts loads of time off conditioning large amounts of clay, makes blending colors a snap and makes consistently even sheets.
I'd also try stamping before deciding which will look best for your project. You can do a lot with a good quality rubber stamp and a little Pearl-Ex or paint. Does the organization you're volunteering for have a local office? Do they have a rubber stamp with the logo? You could ask to borrow it for a day or two to experiment.
