Being that I have only read the original post, I will post the following:
1) If a reputation is partly important to you (which it sounds like it is at least *part* of the reason you are considering leaving), you're in for a treat in the Greek world
Every sorority on every campus will have a reptuation. Some are good (i.e. the sorority that has a reputation for making a GPA of 3.9 every semester and beating the All-Greek, All-Women's, etc. avg. GPA) and some are bad (i.e. the sorority that always parties, etc). Many times "reputations" are not really deserved and sometimes they are just mean things that people say.
2) Sorority life is a 2-way street. You can't expect to magically become best friends with all 100 (or however many) women in your chapter. You have to spend time with them to build the bonds. Why not show a little initiative and call up some of your new member sisters and get together? Maybe you and your new member sisters can have a get together with them and all of their big-sisters. Why not call up your big sister and suggest you order a pizza and watch a movie. While it is true that they are the "active sisters" sometimes school, work, whatever gets overwhelming and maybe forget some of the little things like calling up the new girls and just asking to hang out. Show some initiative. You only get out of Greek life what you put into it. If you sit around and wait for something to happen, you are just going to be become unhappy, mad, and want to leave.... like I said, show some initiative. Maybe you can move into the sorority house? It's a lot of fun and great way to build relationships w/ ppl.
It takes some time to get completely comfortable in a new environment. I joined Delta Sigma Pi (business) and ADPi at different times in my college career. When I joined DSP, at first it was really strange for me. I felt like I didn't know anyone in the chapter, but after awhile, I made some bonds w/ people and it was all great. Then I transferred schools and even though I was already an initatiated member of DSP, when I joined the new chapter, I felt strange all over again. Like I said, it takes awhile to adjust. Then junior year (I transferred after my soph. year) I joined ADPi and I felt the same way all over again. All three times, I adjusted, made friends w/ people and enjoyed college life. It didn't happen overnight.
3) You said "any help would be greatly apprecaited". No one can really help you make this decision. It is all you. You have 2 options: you can stay where you are or depledge and try joining another house. You may or may not get into another house, but that's just one of the risks (for lack of better terms). Since you mentioned the school was Texas, there is a possiblity of their system having "free upperclassmen" during FR, but I think those spots are few and far between. I don't know a lot about Texas rush, but I hear it is very competitive.
4) If you do decide to stay, use your membership as an opportunity to try to help out the sorority. Take an office. Get involved. Is it possible that your chapter is just really overworked from doing continuous recruitment and people are weary from taking on 2 offices to keep the chapter running? Maybe the sorority just needs a few good women to be excited about turning things around to help it succeed.
That's just my take on it though