After you install 7-Zip, right click on the printer driver file you downloaded.
Have 7-Zip Extract to: And let it extract the file into its folder name. You may get some kind of error notification which you can ignore.
Once that is done, use the add printer wizard in the contol panel, and when you are asked to install the driver, click on Have Disk, and browse to the driver folder 7-Zip created>prnhp001, and select the HP Photosmart 3200 series printer from the list, and the driver should install.
If you are unsure of how to manually install the printer, this link should be of help to you.
Start reading from step 3, since you have already downloaded and unzipped the driver.