Mabrouk and welcome to Linux!
First of all, what is the version of Mandriva you are using?
Second, what Desktop Environment are you using? (If you do not know the answer to this one, can you please show me a screenshot?)
I'd suggest you waited a little bit before installing SuSE, though it shouldn't be too hard to do.
About the wireless: Try to install all the updates available (wait the night to do so), it sometimes magically fix your problem. Worse comes to worse, you could either stick with your ethernet cable (try to hide it in a nice fashion so it's out of your way), or try SuSE as a live CD to check if the wireless works.
As for what to do next, I'd suggest moving around Mandriva for a while. Getting a feel for the OS. Use as many apps as you can. You will notice that even though they look similar (Desktop, icons, Panels, menus, ...) Windows and Mandriva have different GUIs.
Try to install a program of your choice. (Tip: You cannot do it like you do in Windows, so don't bother going to the constructor's website to donwload a 'Setup.exe', it won't work).
Try to watch a video on Youtube. It probably won't work. You have to install a Flash codec. Learn to do that.
Try to listen to mp3s. Watch a video. Fix the problems when it won't work.
There are reasons why you cannot use Flash, mp3, mpeg, avi ... natively. The linux world is filled with politics. I'll be glad to teach you why.
Try to install Skype and if you do not use it, learn to "uninstall" it.
Change the theme a little bit.
Set up a LAN network with your laptop. It should be easy as fuck if you have some TCP/IP knowledge.
Mandriva has a very intuitive GUIs. If you try hard enough, by the end of the week end you should be able to do all this stuff.
And when you feel ready, learn how to use the command line. As you will probably notice, it is definitely not necessary to do so anymore. However I'd still recommend you do it because it will give you a power far greater in computing. I wise man once said on this forum, that Linux is
"a gem for the worthy". Learn to be one of them. I found
this tutorial here that should be a good start.
After that there are limitless tasks you can do. You are a web developer. Learn to set up Apache web server on Mandriva. You will see how well it integrates with Linux.
Learn to use a
real text editor like VI or emacs.
Learn to connect remotely to other machines with ssh.
Learn to dual boot with SuSE or Windows, as well as advanced partition systems. (Dual booting means having multiple OS on your machine. You choose the one you want to run at start. In case you do not know).
As you can see, there are a lot you could do and this is just the beginning. More importantly you will notice how fun it is to do them. I have been in the linux world full-time since 2008, and I'm loving every second of it.