There was a scene towards the beginning of the episode where Mr. Bennett and some guy in a white lab coat were talking about Sylar, and I caught something about how he could possibly die in the next couple of days. My friend was talking during that part though, so I didn't catch why. Can someone please explain?

Also, did anybody else notice that the guy in the white lab coat was the same man Mr. Bennett hired to be Claire's "dad" when she thought she was meeting her real parents?

yes i did noticed that.

they were talking about finding the portions in which Sylar altered his dna and they could only find the part dealing wiht his TK

The dude in the lab coat was talking about all the experiments they had run on Sylar and the fact that they couldnt find anything in his DNA that would identify the other powers he'd stolen. Basically saying that they weren't a part of his DNA, at least that they could tell. He told Mr. Bennet that if they kept running tests at the rate they were going, it would eventually kill Sylar.

I see. Thank you guys for clearing that up for me. : )

The powerful and potentially lethal drug that they are administering to Sylar to subdue him could become problematic in the short term while they are attempting to locate the sources of Sylar's powers. The tk power is the only one they have found the source for. And, in spite of the warning that continuing to give Sylar the dangerous sedative drug could kill him, HRG instructs his lab coated employee to continue the search to uncover Sylar's secrets.

yeah for some reason, I couldn't understand what they had said either. I heard something about the drug knocking out an elephant and the drug could eventually kill Sylar.

So they located the source of his TK? interesting...