You can find it on the Huawei web-site.
If you have two different programs that won't even install, I wonder if there is not another problem with your Vista setup?
Not a rights or permission issue?
The User Account Control (UAC) in Vista is a big problem with a lot of driver installations. Turn of UAC before installing any driver. In fact turn it off full stop. If you are paranoid you can always turn it back on.
To turn it off START > CONTROL PANEL > USERS ACCOUNTS > Turn User Account Control On or Off.
Turn it off, reboot and then install your drivers.
While UAC is a good introduction from Microsoft to prevent spyware etc from automatically loading on your pc it does more bad than good with getting drivers and certain software working and can turn a lot of people off Vista before they have even begun. With UAC turned off you will not have problems with any installation.