Site hacked, cleaned up, still unresolved

Last week I was notified by Dreamhost that my blog had been hacked. It looks like it affected my “bye summer” theme. I downloaded and activated the anti-malware plugin and this seemed to have resolved the suspected threat files but there are still 2 lines of text visible at the top of my blog (and dashboard) that I can’t seem to get rid of. I’ve heard that I should delete and reinstall my theme but I’m lost on how I would do that and whether this would compromise any data. Any advice would be much appreciated!