Taurus PT - 1911: About $750
Custom 1911 barrel long enough to accommodate suppressor threads: About $200
Gunsmith fine tuning to fit said barrel on said 1911 and put a decent trigger job on there: About $100-$200
.45 Cal Ti-Rant Suppressor: About $800, plus $200 tax stamp and 6 months of wait time on back ground check.
.45 caliber rounds are already subsonic (less than 1000fps) so a box of ammo is gonna cost you about $20-$25
15 round magazine - About $20
I had to Google what the hell a magnetic laser sight was, because I had never heard the term before. Apparently they are about $100
My math has you between $2250-$2350 not including tax. Start saving your pennies.