ok on looking it seems to have a standard atx sized psu but there isnt much room in the case it looks very cramped inside im not confident you can fit a card of that size in there anyway.
Also it seems to have something taking up the pcie slot.
Without knowing what that is or what it is for it wouldnt be safe to say you could remove it to put something else there.
the blower version of the HD7970 is pretty big as it is and then there are the dual fan versions.
The DVD rom drive in the case comes out into the space where the card would need to sit as they tend to be long.
personaly i would buy a cheap gaming case and transfer everything out into that.
here is a good example of something suitable
https://www.ebuyer.com/803187-avp-x6-mid-tower-white-case-at-ebuyer-com-x6-wh
The first pc i ever tinkered with was a pc world bog standard intel desktop and it was great fun trying to upgrade it but thats when you realise these things are designed for a single purpose.
yes you might be able to do it and maybe get away with it but the airflow in there would be shocking it wouldnt even be worth the ballache.
you can pick up a nice gaming case for like 20 quid these days and you will have far more fun tranfering everything into that.