As for the pitch deck itself, if you have the ability to tell stories and design good looking slides, I'd give yourself 1 week on the first draft and then begin pitching to lower tier investors -- ask them for their take on the presentation and advice. Your deck is a living artifact so you may find yourself throwing out the first version and starting over or just simply iterating on it with each subsequent investor meeting. Regardless, use a template to get yourself out of the gate -- http://newhaircut.com/pitch-deck-design.
If all you can manage to put together is a snoozer that will have your investor questioning your ability to breathe, let alone run a business, get some outside help. This process shouldn't take more than 7-10 days.
I'd spend the majority of your time prepping what an investor really cares about. That is, "how big is the market oppurtunity?" and "How do you generate revenue?". If those two things are compelling enough and you articulate them well, they will want to know more.
Overall I'd say 4-5 hours on the pitch deck and then 1-3 practicing (depending on how confident a public speaker you are). Best of luck!