need help and tips gaining weight (female)

I'm female 5'7 tall and 8.4 stone. i want to put weight on and be 9 and a half stone.
i want to be curvy and thicker.
at the moment I've increased my calories to 2100 calories and try to eat 50% carbs, 30% fat and 20% protein as best i can.

i can only do weight training at the gym 1x per week (i do squats/leg press lunges and a bit of arm work)

I now walk 3 miles per day (1.5 uphill to work and 1.5 back down) 3mph or 3.5 miles per hour depending on how many bags I'm holding.

i need to have meat on my generally as I'm slim but i don't want to end up getting a stomach. fat everywhere else is more than welcome!

any tips to help me? am i doing anything wrong?? any help would be much appreciated.