My first project need a lot of advice

I'm an artist and I'm building things with a cnc out of foam and then fiberglassing etc, and I decided that its time to include the interactive element. However, I bit off more than I could chew because the museum wants it installed on MARCH 8th. (i may be able to get another few days but...)

Okay, so 1st. i need to hook up between one and three proximity sensors 5 foot range with accuracy between .1 and 2 feet. 2nd. when those detect something, for them to start a track and as one gets closer, for that track to get louder and softer as you retreat. (hook them up to speakers) 3rd (ish) If I can finish this in time I would also like to have four light sources that dim as people get closer to the same proximity sensors.

I've been looking at the sharp long range infared sensors for up to five feet and also I found this circuit guide for audio-proximity sensor.. (next post since this is my first)

I would be forever indebted to anyone who could help me. any thoughts? Most helpful would be a rough shopping list (including which arduino..) and if someone has the sketch for this I would probably have a heart attack

(would i even need an arduino for this?)

http://www.instructables.com/id/How_to_Connect_a_Sensor_with_Audio_Input_and_Outpu/

Thanks, thats really helpful. I have a few professors who could help me along with the code and the wiring I could probably get worked out. I'm really just trying to find someone (locally or online) to walk me through this project so that I could do the next one completely on my own. Those products by the way seem perfect. I was hoping infared would be fine because of budgeting for 3 of them but yeah, ultrasonic seems more legit. If anyone else has a sketch or something that's similar for me to edit, that would be great (especially one using that mp3 trigger board). Or if anyone in Florida would like to get on board with me that could be arranged.

Yeah, I realize that now which is why I plan on doing something with the Ping Ultrasonic range finder. I'm thinking now that I'll just wire one of those directly to the arduino and install the wav shield from adafruit (http://www.adafruit.com/index.php?main_page=product_info&cPath=17_21&products_id=94). I've found a sketch to make the ping))) control midi tones but still no luck modifying it for volume/start track. Any thoughts?

Both; this is my first project and there's a lot of things I haven't had the time to understand yet. Right now I'm trying to knit the ping sketch with the softVolumeChange sketch for the wavshield. I'm looking at the screen and have 200 pdfs of code lying around and as embarrassing as it is, its all greek to me. I have a basic understanding of what each line means individually but i just dont know how to change it. :-/