Welcome from another new memebr and short cyclist (5'2")! I have had my entry bike approximately two years and have added new handlebars, pedals and tires. The entry level will serve you well and help you figure out what you like. Mine is an entry level Fuji, I think it was about $600-700.

My husband got me into cycling but my parents and brother thought I was crazy. We were a bowling family, but a movement disorder caused me to drop bowling. Now my parents are understanding my passion, even driving my husband and I the three hours to Houston to start the MS150 next weekend! your family will warm up to the idea when they see your passion. My parents work for the state, so I had to laugh at your budgeting because I completely understand!

Good luck training for the ride, with dedication 45 miles will come easily. Congrats on the weight loss, I lost about 30 lb two years ago and I know that struggle. You will be surprised that you don't have to be rail thin to be a cyclist. There is a huge mental aspect- you can do it!