Actually my iphone 4s continuously keeps on searching personal hotspots

http://support.apple.com/kb/HT4517

http://support.apple.com/kb/TS2756

Actually your statement makes no sense.

general - cellular - cellular data network - scroll down to internet tethering fill the APN entry space with the same you have filled for your cellular data apn.

now just turn on and off the cellular data by just toggling . the problem will be solved.

first reset ur ineternet settings and then only yu do the above .