Any tips for first-time gym-goers?

My husband and I joined a local gym today. I’ve never been to a gym before and was always really apprehensive about the idea. All I could picture was me and my less-than-ideal figure surrounded by these skinny, ripped, and/or tan hotties working out. Well, I’m about to get over that, because this weight has got to come off and I honestly don’t have the self-discipline to do any meaningful exercise on my own and stick to it.

This particular gym is brand new and within walking distance of our house. It’s on the smaller side, so no pool/steam room/tanning beds/etc., but all of the equipment is brand spankin’ new and, luckily, it’s not usually packed with people. My husband and I will be going together Monday-Friday between 7 and 8 at night (about an hour after dinner). He’s looking to bulk up, so he’ll be focusing on weight lifting while I’ll be primarily using the cardio machines (treadmill, elliptical, etc.) until I drop some initial lbs.

I’ve read about gym etiquette – wiping up sweat, not hogging machines, making sure there’s no line for a machine before you hop on, etc. However, I’m wondering what machines I should use and for how long, taking into consideration that I’m a beginner, to get good results in a reasonable amount of time.

I’m only looking to lose 15 pounds, then tone up, and then maintain my new and improved figure over time. I was thinking I could do 30 minutes on the treadmill, because I’ll be (hopefully) attending the police academy early next year and will need to be able to jog and keep up with the boys there in all of the physical activities required. As it is, I can’t jog for more than 30 seconds without my side hurting. Yes, I’m in awful shape even though I may not technically be all that overweight. I figure I’ll work my way from power-walking to jogging over the next few weeks. But, what other machines should I use in the remaining 30 minutes? Should I switch it up – new machine every day – or keep it consistent?

Also, I’ve been restricting my calories to 1200 per day (I’m 5’5” and about 145 lbs) with very light exercise and I haven’t been losing squat. With an hour of cardio, give or take, would 1200 still be alright?