Download the file of an alternate browser using a different computer, & transfer it to your current computer using a USB stick or CD
Internet Explorer is just too dangerous to keep using:
In the past, several governments have warned their people to stop using Internet Explorer because of serious vulnerabilities
http://www.abc.net.au/news/2010-01-19/govt-issues-ie-security-warning/1214238
And recently the German government has repeated this warning
http://www.telegraph.co.uk/technology/microsoft/9552462/German-government-warns-users-off-Internet-Explorer.html
Microsoft has since fixed these extreme vulnerabilities, but unfortunately, there are still 45 more open vulnerabilities that have never been patched
http://www.securityfocus.com/cgi-bin/index.cgi?c=12&vendor=Microsoft&version=%209&title=Internet%20Explorer