Replace a yale lock

[chazmate]

Hello.How can i open a metal door that has a yale lock on it.The lock has been tampered with and will not open with the key.There is no other way for me to get into building other than the door but this as stated i cannot do.Have to do this myself as cannot afford a professional to do it for me.I have a new security lock to replace with.It is 2.5inches from door edge to centre of yale key hole.All advice would be greatly recieved.

Chazmate :!: