Tumblr app for iPhone 4 not working, help?

I went to the app store about a week ago and my Tumblr app needed an update so I updated it. Now everytime I click on it it just exits out back to my home screen. I left it alone for a while because I thought it was just my phone acting up but over the course of the week I kept trying to click it day after day and it wont open, just exits out to my homescreen. I suspect it's because this update of Tumblr was created for the iOS 6.1.3 software update for the iPhone but I can't get it because I need 2.7 GB of available storage but I refuse to delete any apps or pictures or music for a software update I don't care to download in the first place. I simply made the mistake of updating my Tumblr app and now I can't access it. Right now my softward is not 6.1.3 but 5.0.1 and I'd like to keep it this way. But I would also like my Tumblr app back. I do not like the safari version of Tumblr either so I don't use it. Is there a way to either get my old update of Tumblr back or something? If you could help me that'd be a tremondous help. I just want my Tumblr app back and working. Thank you.

Delete the app & install it again, if that doesn't work restart your IPhone by pressing the home & lock button & wait until it starts working.

I have same problem, only I can't restart as my power button is frozen so I can't restart manually. A safari version was mentioned. Does this wotk, whether convenient or not? I don't have internet access so am at mercy of my iPhone