You're not even trying are you?
gawk "{print $2\",\" $3 }" 1.txt
318349.74,4231547.73
318445.61,4231568.79
318446.37,4231561.59
318443.36,4231549.82
318438.82,4231539.87
318428.56,4231532.33
318425.25,4231523.57
318428.55,4231513.05
318442.57,4231516.64
318455.87,4231506.94
318473.12,4231495.81
318473.84,4231490.78
318468.81,4231486.11