How to get my original ROM working again?

How to get my original ROM working again?

I have a Samsung Galaxy Ace GT-S5830L and I a few days ago downloaded and
installed a custom ROM 4.2.2 the name of the file is
(cm-10.1-20130503-NIGHTLY-cooper), It worked good at first, but then the
apps didn't download it used a lot of memory, it crashed/hanged and it
became annoying, So I'm trying to return to my previous original version
2.3.4, but It doesn't work... I made a backup with clockworks, but it
doesn't work. I tried downloading one from the internet and using thor (i
think that was its name) to install it, but it doesn't connect succeed
anytime I try... I also tried with kies, but It didn't work, it just staid
there for hours without doing anything...
So what are my options to restore the original ROM?, I really need to get
back to it, this version is just to buggy and annoying for me to stay with
it.