Need expert opinion on 1TB FreeAgent pro SATA adapter from inside please

Hi, I've decided to pass on my external's 5 year warranty because it worked 1 year perfect, this means it will in the future and I don't use it too much anyway.
I've hardly managed to open the enclosure and I want the SATA HDD inside replaced, because it's full of backup and it's place is in the closet.
The thing is, I want to buy a larger HDD to take it's place inside, a 1.5TB or 2TB seagate preferable but I don't know if it will be supported by the SATA adapter inside. Some friends say it should be possibile 90%, but I can't be sure of that because I've seen on the market separate enclosures with GB or TB limit on the specs.
I've tried this before putting a smaller HDD, but never a larger so I'm afraid that I'll buy for nothing a new HDD that won't work. I don't have a PC, only a laptop so I can't risk having it on my desk doing nothing. I'm out of money to buy another external, because the $ difference between that and internal is pretty big in my country and I also don't have a job anymore.
If anyone know's if this is possibile to support or if anyone out there ever tried this before, even on lower combinations (eg: 750gb hdd on 500gb enclosure) please let me know.
Thank You!