Yes, Donald Trump did make this statement in a 2015-06-29 press conference:
You have 20 million, 30 million, nobody knows what it is. It used to be 11 million. Now, today I hear it’s 11, but I don’t think it’s 11. I actually heard you probably have 30 million. You have to give them a path, and you have to make it possible for them to succeed.
This press conference was aired by CNN on the July 3rd episode of Situation Room in a series of various video clips of Trump under the topic "Outrage Grows as Trump Keeps Talking about Mexicans".
allegedly Donald Trump: The biggest problem is that you have some great, wonderful people coming in from Mexico that are working the crops, they’re working cutting lawns, they’re doing a lot of jobs that I’m not sure that a lot of Americans are going to take those jobs. And that’s the dichotomy. That’s the big problem because you have a lot of great people coming in doing a lot of work, and I’m not so sure that a lot of other people are going to be doing that work. So, it is a very tough problem, but I do say this, you have a law, or at least you have to establish a law, and I guess we’re sort of a country and other people aren’t supposed to be coming into our country illegally.
The above statement purported to be uttered by Donald Trump is also not present in Bill O'Reilly's interview with Trump in 2011 and seem to be simply inserted between actual interview transcripts of the 2011 O'Reilly Factor show. The unedited videos are present here and here.
The actual order of conversation between Bill O'Reilly and Donald Trump in the interview are as follows (tried my best to match the exact words spoken and with reference from Glenn Beck Program column).
The question about illegal immigration to Donald Trump starts in this 2011 interview with Bill O'Reilly.
Now, the 15 million illegal aliens already in the United States, what do you do with them?
What do you do with the 15 million here, do you give them a pathway to citizenship or you put them on a bus and drive them out from here?
I think right now you’re going to have to do something, and you know it’s hard to generalize, but you’re going to have to look at the individual people, see how they’ve done, see how productive they’ve been, see what their references are, and then make a decision.
All right, on a case-by-case—going to take a long time and a lot of people.
A long time, but you know, you have some great, productive people that came and then you have some total disasters that probably need to be in prison.
Then the interviewer Bill O'Reilly moves to social issues (abortion) questioning to Donald Trump.