Batch, 322 310 bytes

@echo off
set/pi=
set/aa=0,b=1,c=2,d=3,e=4,f=5,g=6,h=7,j=8,k=9,l=10,m=11,n=12,o=13,p=14,q=15,r=16,s=17,t=18,x=%i:~1%-1,y=%i:~0,1%,z=y+1
for /l %%r in (18,-1,0)do call:l %%r
exit/b
:l
set s=...*.....*.....*...
call set t=%%s:~%1,1%%
if %x%==%1 call set s=%%s:~0,%y%%%o%%s:~%z%%%
call echo %%s:.*=.%t%%%

Explanation: Starts by prompting for the stone on stdin. Then, sets variables for each possible column, so that it can evaluate the first character of the stone as a variable to get the y coordinate. Subtracts 1 from the x coordinate because it's 1-indexed and we want 0-indexed and also computes z=y+1 as it will need that later. Then, loops r from 18 down to 0 for each row. Takes the string ...*.....*.....*... and extracts the character at the rth position for later. On the xth row, the yth character is replaced with an o. Finally, the .*s are replaced with a . plus the previously extracted character; this is a no-op on rows 4, 10 and 16 but this is the shortest way to achieve that. (I have to use .* because replacing * is apparently illegal in Batch.)

Batch, 322 310 308 bytes

@echo off
set/pi=
set/aa=0,b=1,c=2,d=3,e=4,f=5,g=6,h=7,j=8,k=9,l=10,m=11,n=12,o=13,p=14,q=15,r=16,s=17,t=18,x=%i:~1%-1,y=%i:~,1%,z=y+1
for /l %%r in (18,-1,0)do call:l %%r
exit/b
:l
set s=...*.....*.....*...
call set t=%%s:~%1,1%%
if %x%==%1 call set s=%%s:~,%y%%%o%%s:~%z%%%
call echo %%s:.*=.%t%%%

Explanation: Starts by prompting for the stone on stdin. Then, sets variables for each possible column, so that it can evaluate the first character of the stone as a variable to get the y coordinate. Subtracts 1 from the x coordinate because it's 1-indexed and we want 0-indexed and also computes z=y+1 as it will need that later. Then, loops r from 18 down to 0 for each row. Takes the string ...*.....*.....*... and extracts the character at the rth position for later. On the xth row, the yth character is replaced with an o. Finally, the .*s are replaced with a . plus the previously extracted character; this is a no-op on rows 4, 10 and 16 but this is the shortest way to achieve that. (I have to use .* because replacing * is apparently illegal in Batch.)

Batch, 323 bytes

@echo off
set/pi=
set/aa=0,b=1,c=2,d=3,e=4,f=5,g=6,h=7,j=8,k=9,l=10,m=11,n=12,o=13,p=14,q=15,r=16,s=17,t=18,x=%i:~1%-1,y=%i:~0,1%,z=y+1
for /l %%r in (18,-1,0)do call:l %%r
exit/b
:l
set s=...+.....+.....+...
call set t=%%s:~%1,1%%
call set s=%%s:+=%t%%%
if %x%==%1 call set s=%%s:~0,%y%%%o%%s:~%z%%%
echo %s:+=*%

Batch, 322 310 bytes

@echo off
set/pi=
set/aa=0,b=1,c=2,d=3,e=4,f=5,g=6,h=7,j=8,k=9,l=10,m=11,n=12,o=13,p=14,q=15,r=16,s=17,t=18,x=%i:~1%-1,y=%i:~0,1%,z=y+1
for /l %%r in (18,-1,0)do call:l %%r
exit/b
:l
set s=...*.....*.....*...
call set t=%%s:~%1,1%%
if %x%==%1 call set s=%%s:~0,%y%%%o%%s:~%z%%%
call echo %%s:.*=.%t%%%

Explanation: Starts by prompting for the stone on stdin. Then, sets variables for each possible column, so that it can evaluate the first character of the stone as a variable to get the y coordinate. Subtracts 1 from the x coordinate because it's 1-indexed and we want 0-indexed and also computes z=y+1 as it will need that later. Then, loops r from 18 down to 0 for each row. Takes the string ...*.....*.....*... and extracts the character at the rth position for later. On the xth row, the yth character is replaced with an o. Finally, the .*s are replaced with a . plus the previously extracted character; this is a no-op on rows 4, 10 and 16 but this is the shortest way to achieve that. (I have to use .* because replacing * is apparently illegal in Batch.)