Another Vote for the FAA Instrument Flying Handbook.
I own both books, the FAA's and Jeppesen's and find the FAA book by far better as a reference. However I did use the Jepp as my main preparation tool for my Instrument written together with Jeppesen's Guided Flight Dicovery IFR-CD, but after my checkride I now find myself using the FAA book more often.
I would recommend buying the FAA Instrument Book and see if it's enough for you. It's just around $20-25, so money should be no factor and in case it's not sufficient for you, you still have a good refernce book after your checkride!