Hi Jaetee,
Are you looking for something that you can clip into a stroller or are you happy to carry the car seat around when you get to your destination?
I have spent months looking for something to safely transport my 12 month old in a taxi. I am a bit of a weakling so don't think I could carry a car seat and push my little one in a pram and carry the shopping all at once!
In the end I ordered a couple of items from the US. A "Joey Safe" and something called "Travel Vest" (the latter via Amazon.com). These are not car seats but work as travel harnesses. These are obviously not as safe as a proper car seat but the Travel Vest is approved in the US by the relevant government authority and meets US standards (it wouldn't meet Australian standards I should add). These products are aimed at the 2-5 year age group (they are too big for my little one). If you google the names of the products you will be able to read about them.