Hi there-
The best advice I could give you, and it is what I would tell my sister, is that you first must firmly decide what you would like to look like, taking into consideration all of your other thoughts about your preferred lifestyle, clothing choices, etc...
Once you have a good understanding of the appearance that you want to present to the world; the one that will keep you smiling as you walk by mirrors and shop windows, then it's appropriate to research the options for achieving that look.
It is my opinion that, depending on the above, you could achieve a very pleasing and natural outcome by removing the current implants with their associated scar tissue, and replacing them with new implants under your muscle. At the time you had the initial operation the prevailing wisdom differed from today- but I can tell you that placement of textured saline implants on top of the chest muscle is not a technique I would ever recommend nowadays...
Alternatively, removing the implants and having a breast lift would also give you pretty breasts- but they would of course be smaller and less full. Only you can decide whether the scars of a breast lift are worth it or not, and of course, this depends a lot on the way they heal...
Your decision should be based on whether you prefer the breast size and silhouette you currently enjoy, or if you would rather be free of the implants, have smaller breasts, but with some additional skin scars. (BTW, the scars don't need to be heinous- find a surgeon who can show you photos of prior patients with scars that are thin and inconspicuous).
