Both the sentence presented
I already have two stamps drawn.
and the one Irene presented
I have already drawn two stamps.
are completely grammatical, and mean the same thing. They are not, however, the same construction, and have slightly different grammars.
Irene's sentence is the Present Perfect construction of the verb draw, and it does imply (though not guarantee) that drawing will continue, because of the Present Relevance feature of Present Perfect. (The already helps there, too.)
The original sentence, however, is a different construction, also using have, but with a noun phrase direct object — i.e., "what I already have" — of two stamps that are drawn, with a restrictive relative clause on the same pattern as
- I already have seven chapters that are finished.
- I already have three bags that are full
This is reduced by Whiz-deletion to two stamps drawn, like
- I already have seven chapters finished.
- I already have three bags full.
This construction (again helped along by use of already) also implies, perhaps somewhat more strongly — because it's more specialized — than the present perfect, that this is ongoing effort and this is just the first product.
The placement of already is different, too. Already has to go either after the first auxiliary verb or, if there are no auxiliary verbs, before the main verb.
In the Present Perfect, have is an auxiliary verb, so already has to follow have, as Irene says.
In the other construction, however, have is the main verb, and there are no auxiliary verbs, so already has to precede have.