Enaver, have you installed Magic Lantern on your 550? If not give that a go first, turning the AGC off will make quite a difference and it's free. As I understand it you are just shooting for yourself to get ideas down and experiment but can't hack the terrible audio. If that is what you are after you may well be satisfied with getting a cheap boom, extension cable and running that rode into your 550 without AGC. Cost's nothing to try a test shot with the mic hand held or camera mounted with the camera in close (only really worried about the audio here so don't worry about your shot).
Magic lantern is very easy to install and you only have to flash the camera once. And if you want to revert to normal you just use an SD card without the software on.
If that does not deliver the quality you are after then Alcove's suggestion will be another great step forward but you have to spend for that.
to give you an idea the following clip was shot with a camera mounted mic going straight to cam.
http://vimeo.com/20993192
Technically my mic (me66) is better than the rode but the Rode is better matched to the 550 inputs so may actually give better results. Was shot with a 50mm lens to give you an idea of how far away the mic is positioned (one full pavement's width away, much further than a boomed mic should be).
It's not great but if you find it acceptable then you only need to spend on boom, mount and cable (my hookup is balanced but yours probably won't be). Of course being cabled up to the camera is not ideal and if you do have the money get the recorders Alcove mentioned, they are a much better way of doing things.
If you are taking separate audio give pluraleyes or dualeyes a look, will save you hours and if you are a student you can get them half price.
As for doing it by hand always make sure you take guide audio on cam (also essential for pluraleyes to work) use a clapper if you can and line up the transients. You will hear the two soundtracks phasing against each other once you are close and just slip the audio frame by frame until the phasing stops. It's time consuming but not a terribly difficult job.
Just noticed you also mentioned wind noise. Whatever approach you use you will need some good wind protection for your mic. Rycote do a nice kit with slip on blimp, furry cover and shock mount for on cam or boomed. The wind protection is not as good as a full on blimp and I have had problems in a stiff wind (riverside) but been fine in normal breezes. Not sure if they do one for the rode tho