Replying to Can someone PLEASE help me with video AUDIO?

I'll try to keep this short and sweet, and anyone that can help me will be a lifesaver.

I need good audio for my T3i. I'm starting to do more and more video for a company and we need good audio.

I had about a 2 hour talk with a dude from B&H Photo today, and it helped me somewhat, but I'm still not at the place of understanding that I need to be at, simply because I've been doing video for years that never required audio.

Basically, I need audio equipment for all of these types of situations:
One person interviews
Two person interviews
Events
Skiing
etc.

To start, I got a $150 Azden lavalier mic. This mic is not great by any means. Frankly it kind of sucks. It has a terrible hiss to it. So before I went any further, I wanted help.

I understand that I will probably need another lav mic (2 total) and a shotgun mic, along with some type of pre-amp/mixer if I want decent audio and want to get rid of the hiss. I understand this is because the amp in the Canon DSLR sucks.

The company will be able to buy stuff, but we can't go crazy here.

So basically what I'm asking is these 3 things:
1. To anyone who works with audio frequently on a DSLR, What are you achieve clear audio?

2. What should I be buying?

I'm not asking for downright amazing audio. Just audio that is hiss free and clear in every situation. And BTW, I'm editing in Final Cut Pro X.

If anyone can help me with this, that would be amazing. If you have videos to show, tips, tricks, etc. I'd be so grateful.

Thanks