Radioshack may make electronic hobbists look rich. The fact is that radiocrap is only good for perf boards, and assorted 22 gauge wire. I buy their solid gauge wire because it works well and I like it. If you want a really good and cheap supplier of electronic components, go to jameco.com. They are nice and cheap, and I buy stuff from them all the time. At my radiocrap store, I dont even look at the labels of the part bins its that unorginized. Radiocraps soldering iron tip disintegrates fairly quick, so you may want to stock up. Make sure you have the following before you start to solder:
Nonflammable work bench
Sponge
Baking soda (for electrical fires)
Soldering IRON (not the gun)
Solder
Solid gauge wire (22gau)
A basic idea of what your doing.
You may want to study up on the components of what your using before you solder. You may also want to "prototype it" on a breadboard to make sure it works.
As for D1 and D2, they are probably phototransistors or just IR LEDs. Go to the study section of that kpsec.freeuk site first to study up. Since you are new, you may want to sample some stuff first. Go to the "gotta love ripping off free samples" thread and look at some of the companies offering samples. Just get one of somthing to try it out. Dont abuse it, or it may not be there.
Any questions? PM (private Message)me!
NOTE: That kpsec site is REALLY good for a beginner, so look at "how to solder", and "study" section. Read uP!