The Android Market is all you will see on Android 2.1, which is what your handset has. Only handsets with Android 2.2 and up get the Google Play Store app. I think, however, your problem is related to the missing microSD card. Try throwing a microSD card into your handset and seeing if it will let you sign into the Android Market.
If that does not work, then you should make a post in the root section of this sub-forum which can be found here: Sprint Hero - All Things Root - Android Forums
. We will gladly help you get Android 2.3, in the form of CyanogenMod 7.2, set up on your handset. Android 2.3 offers better battery life, smoothness, and other new features, anyway.