I'm afraid I agree. Think about this from a "what if" perspective... worst case scenario is 200 gallons of water on your floor and fish flopping around with nothing to put them in? 2nd worst is slow leak... still needing a place to put fish while you repair the tank.
I have resealed a small tank, 10 gallon, it's fussy but do-able...but never replaced a panel of glass. Any tank repair places near you to call and cost it out?
I've had 45 gallons on my floor and that was horrendous to say the least... and that was only a slow leak that I found after it happened... or while it was happening.
This could lead into ruined carpet and flooring costs too not just the cost of the glass repair, it's a lot of water.
Let us know what you decide to do! Good luck.