Gym and repetitions?? (trainers or experienced please) :-)?

im just joined the gym and i weigh 129 and am 5'5 i want to tone tone tone and lose some fat!! i stay on the eleptical for 50 minutes monday wednesday and friday. then on tuesday thursday and saturday i do weight training but im not sore AT ALL and so i was thinking to up my weight a bit and do more reps as of right now im doing 1 rep with 12 sets. i think that is WAY to easy!! should i start eating ALOT more protein and fats but less carbs??