Generally speaking - yes - you do have the right to see it or refer to it (or a copy of it). You do not have the right to have it back.
In some legal systems, the offender may have the right to see the witness statement, but usually personal information is redacted to protect the witness's privacy. The court usually determines what information can be disclosed to the offender.
What witness statement, in what case?
yes
he killed himself, becasue Johnny died and he had to witness it right in front of him. He died near the park right under the street light, where everyone can see and witness how he fell and died.
On witness's statement to investigators - no. On the usability and admissability of them in court - yes.
A person who gives a statement is called a witness.
Absolutely.
Hearsay
This is hearsay, which is a secondary source of information that is not allowed.
Generally, written testimony is unavailing if the other side does not have a chance to cross-examine the witness. It doesn't hurt to try, though, if that's the best you can do. A notarized statement might be very helpful to establish damages if the other side defaults (does not show up) and you can be awarded whatever damages you can prove.
No, a written statement will not suffice in place of your appearance. No written statement by a witness is acceptable even if it is made in the form of an affidavit or certification, because the other party is not able to cross examine a written statement. Nor would the finder of fact able to see the witness testily in order to judge his or her credibility. The only way possible would be if all parties either agreed to allow it or if they stipulated to the facts in the statement.
The most common method of impeaching witness testimony is with a prior inconsistent statement. For example, if a bystander witness watches an accident, she will give a statement to a police officer at the scene. If she told the officer that the traffic light was red, but later testified that the light was green, her statement in the police report could be used to discredit, or impeach, her testimony.