Don't know what to do now!?

[noname94]

Hey so I've been going to the gym for about six months now and I'm doing pretty well. I have mostly been doing weights and have completely lost interest in cardio over the past two or so months...tried doing some treadmill yesterday and got so bored I couldn't last past 5 minutes D:

I weigh about 55kg and feel pretty strong but would now like to tighten my muscles particularly on my arms

I'm just wondering how best to do this without losing muscle that I've grown and if there is anyway to do this with limited cardio...I can't stand it... (unless it's boxing but they took the one away that my gym had)

Please help :s. I currently go about 6 days a week doing arms on one day, legs the next and abs/back after that, then repeating the cycle.