Can't authorize my PC

I can't transfer my apps downloaded in my PC (windows 7) to my iPad (but the vice-versa is possible). Everytime i connect my iPad to my PC it asks for authorization. I de-authorized & authorized it again many times, i followed the steps of this also http://support.apple.com/kb/ts1389 but no use, still it asks for authorization. I uninstalled iTunes & reinstalled also(11.1.3 version). I've a dongle which has a monthly data plan, so for me it is convenient to download my apps through PC & transfer to my iPad. Plz help me. thanks in advance