Patent. Inventions. I have this super dumb/great idea that is 100% for sure to sell easy. It's so great!?

I can mention so little about the product I have.(legalities) but this is a baby item and will 100% sell and it is not around. I have not searched it through any Search Engine on the internet because I know this is NOT around and SHOULD be. This comes from having my first baby. How do I patent the idea and how much so that no one can take it. Also if I patent the idea and it's pretty simple what I want; how do I stop anyone that is established like these new big companies that are around from doing the same thing and marketing it so much faster then me off MY OWN idea and go above and around me? I feel so great about this that I have learned to go to the patent web sight for America in DC and search it their in their archives . Ok so lets be quick if this idea is not taken can I make it mine where no bigger company can take the same idea just do this little different thing that makes it different so they can use my idea to sell. I figured.. work out the patent and I hear it's cheap just to hold the patent as mine until I pay the full scale 10k to really make it mine. Then I figured I can try my hardest to set up a meeting with walmart first and show them a demo and keep them as strictly the ones that carry it or open carry and let me be able to sell to other stores. (I can not express how GREAT this idea is. I know .. I know everyone has one. I have ton's of others just this one I am willing to put in the money for. I'm curious how do I make it mine, I am curuious how to market it,(tv would be great) I am also curious on how to design it the way it will be at the store, Who do I speak to about making this idea, also if I just used things that were out their already is that legal or do I have to pay the person for their idea to make mine work.. This idea is 100% and you will see this around store and TV. I can promise.. I just need the help. I'm so stuck and need this help really bad.. Goranivic2@yahoo.com is my main email if someone is serious in helping out. I also am willing to take on a partner if they know about how to do everything, and we can work out the profit split at that time. I know I have 20+k to invest and I know it will sell 100%.. Most important this idea is SUPER CHEAP.. I cant see it costing more then 1 dollar tops if we had a company produce it.. I mean maybe 1 dollar most likely 20-50 cents.. and it can retail easily at 10 bucks for everyone expecting a baby to get in their baby shower , and 20 would not be a hard sell if we just upped the version just a tiny bit.. Serious people only please, because this is very serious for me.