Help!! How do I guarentee Landlord will let me out of Lease? Iowa

[MDN]

Hi everybody,
I live in Cedar Falls Iowa. Our winters are really cold, and my landlord has failed to provide heat to my apartment. Under Chapter 562A.21 of the Code of Iowa it states:

"if there is a material noncompliance by the landlord with the rental agreement or a noncompliance with section 562A.15 materially affecting health and safety, the tenant may elect to commence an action under this section and shall deliver a written notice to the landlord specifying the acts and omissions constituting the breach and that the rental agreement will terminate upon a date not less than seven days after receipt of the notice"

So basically his failure to provide heat breaks the code of Iowa. As well as a lack of heat, there is also no electricity in my shower room (which is separate from the bathroom, its a POS apartment) and water has begun leaking from my ceiling. I sent my landlord this letter:

Saturday December 2nd, 2006
Dear Landlord,
This letter is in regard to my tenancy at: ________________.
Because you have failed to comply with the rental agreement, Iowa Tenant Landlord Law, or city housing codes, I am using the remedy provided by Chapter 562A.21 of the Code of Iowa.
The following major problems exist and have not been repaired: No electricity to the shower room and a lack of substantial heat in the apartment kitchen and living room/bedroom. The kitchen lacks heat entirely whereas the bedroom/living room has been recorded at an average of 54 degrees. Water has also been leaking from my ceiling the past 3 nights (starting November 29th, 2006). Since I have the right to these essential services, I am taking steps under the Landlord-Tenant Law to correct the situation.
The rental agreement for the property listed above will terminate in seven (7) days from the date you received this notice, unless you fix the problem(s) within the seven (7) days.
If the problem(s) is/are corrected within the seven days, this rental agreement will continue. If the problem(s) reoccur within six months, this rental agreement may be terminated with a single seven-day notice. Further action may also be taken if you fail to perform your duties.
Please act accordingly.
Sincerely,

(I took out my name and the residence address from this posted letter).

What I am asking is how can I ensure that he lets me out of my lease, and how can I make sure that this wont turn into a He said She said arguement in court? Can I get this letter notarized, and would that do anything? Can I send the letter to the courthouse for them to put it on record? Basically, what do I have to do to make the landlord sign a paper saying im out of the lease? Any help is greatly appreciated, thanks!