You need to fix it since the broken coil spring is affecting your ride height. A change in right height will cause alignment problems. In a short period of time, it will cause your new tires to wear unevenly. In addition,as MGregoir said, this is unsafe.
Like I mentioned in the other thread, I would use this opportunity to replace all four struts and the front strut mounts. Saturn struts do not last very long and yours are probably long overdue at 109k.
A set of four KYB struts cost $220 shipped. They ride a bit firm, but a lot of people are very happy with them. A set of front KYB strut mounts cost ~$70 shipped. Since your spring is broken, a set of front coil springs cost about $60 shipped.
I replaced all four struts with a friend in less than two hours. After the job, you'll need a 4-wheel alignment, which costs about $85. Be sure to have the alignment rechecked after a few weeks since the struts will settle and cause the alignment to change slightly.
If you are uncomfortable with compressing the coil spring, you can purchase pre-assembled Monroe "quick struts" for about $125/each.