If you've kept a back-up copy, upload it the way you did it first time.
Did you create it locally (ie, on your PC at home/work) or did you do it on server-based software that many ISPs provide? - that system allows you to create your page on-line and when you're finished it is uploaded automatically to your web space.
If the former, you'll have to dig out your back-up and upload it again to your ISP's webserver. If you don't know how to do that, contact your ISP's helpdesk. You'll need an FTP client such as CuteFTP or some such to do that. If you don't have a back-up you're stuffed - start again, mate!
I've not used the second method, so I don't know if those on-line web page creation progs save a back-up. My guess is they don't, they just save to your webspace. In which case, if that's the method you used ...
Once you're up and running again, it would be wise to keep a back-up copy of your website somewhere.
Not much good news, I'm afraid.
AA