I would suggest that you spend money and hire a patent professional if you think your invention is imporatnt enough. Because stakes may actually be very high on patents (take the recent Blackburry lawsuit, RIM v. NTP, in the U.S.) DIY may cost you a lot in the future, although you save some now. There are too many strategies going into a patent application and a lay person will not get the hang of it just by reading Patents for Dummies or other similar references.
You can send me a private message if you want to discuss more about it.